chore(deps): update dependency pillow to v7 (#3218)

This PR contains the following updates:

| Package | Update | Change |
|---|---|---|
| [pillow](https://python-pillow.org) ([source](https://togithub.com/python-pillow/Pillow)) | major | `==6.2.2` -> `==7.1.0` |

---

### Release Notes

<details>
<summary>python-pillow/Pillow</summary>

### [`v7.1.0`](https://togithub.com/python-pillow/Pillow/blob/master/CHANGES.rst#&#8203;710-2020-04-01)

[Compare Source](https://togithub.com/python-pillow/Pillow/compare/7.0.0...7.1.0)

-   Fix multiple OOB reads in FLI decoding [#&#8203;4503](https://togithub.com/python-pillow/Pillow/issues/4503)
    [wiredfool]

-   Fix buffer overflow in SGI-RLE decoding [#&#8203;4504](https://togithub.com/python-pillow/Pillow/issues/4504)
    [wiredfool, hugovk]

-   Fix bounds overflow in JPEG 2000 decoding [#&#8203;4505](https://togithub.com/python-pillow/Pillow/issues/4505)
    [wiredfool]

-   Fix bounds overflow in PCX decoding [#&#8203;4506](https://togithub.com/python-pillow/Pillow/issues/4506)
    [wiredfool]

-   Fix 2 buffer overflows in TIFF decoding [#&#8203;4507](https://togithub.com/python-pillow/Pillow/issues/4507)
    [wiredfool]

-   Add APNG support [#&#8203;4243](https://togithub.com/python-pillow/Pillow/issues/4243)
    [pmrowla, radarhere, hugovk]

-   ImageGrab.grab() for Linux with XCB [#&#8203;4260](https://togithub.com/python-pillow/Pillow/issues/4260)
    [nulano, radarhere]

-   Added three new channel operations [#&#8203;4230](https://togithub.com/python-pillow/Pillow/issues/4230)
    [dwastberg, radarhere]

-   Prevent masking of Image reduce method in Jpeg2KImagePlugin [#&#8203;4474](https://togithub.com/python-pillow/Pillow/issues/4474)
    [radarhere, homm]

-   Added reading of earlier ImageMagick PNG EXIF data [#&#8203;4471](https://togithub.com/python-pillow/Pillow/issues/4471)
    [radarhere]

-   Fixed endian handling for I;16 getextrema [#&#8203;4457](https://togithub.com/python-pillow/Pillow/issues/4457)
    [radarhere]

-   Release buffer if function returns prematurely [#&#8203;4381](https://togithub.com/python-pillow/Pillow/issues/4381)
    [radarhere]

-   Add JPEG comment to info dictionary [#&#8203;4455](https://togithub.com/python-pillow/Pillow/issues/4455)
    [radarhere]

-   Fix size calculation of Image.thumbnail() [#&#8203;4404](https://togithub.com/python-pillow/Pillow/issues/4404)
    [orlnub123]

-   Fixed stroke on FreeType &lt; 2.9 [#&#8203;4401](https://togithub.com/python-pillow/Pillow/issues/4401)
    [radarhere]

-   If present, only use alpha channel for bounding box [#&#8203;4454](https://togithub.com/python-pillow/Pillow/issues/4454)
    [radarhere]

-   Warn if an unknown feature is passed to features.check() [#&#8203;4438](https://togithub.com/python-pillow/Pillow/issues/4438)
    [jdufresne]

-   Fix Name field length when saving IM images [#&#8203;4424](https://togithub.com/python-pillow/Pillow/issues/4424)
    [hugovk, radarhere]

-   Allow saving of zero quality JPEG images [#&#8203;4440](https://togithub.com/python-pillow/Pillow/issues/4440)
    [radarhere]

-   Allow explicit zero width to hide outline [#&#8203;4334](https://togithub.com/python-pillow/Pillow/issues/4334)
    [radarhere]

-   Change ContainerIO return type to match file object mode [#&#8203;4297](https://togithub.com/python-pillow/Pillow/issues/4297)
    [jdufresne, radarhere]

-   Only draw each polygon pixel once [#&#8203;4333](https://togithub.com/python-pillow/Pillow/issues/4333)
    [radarhere]

-   Add support for shooting situation Exif IFD tags [#&#8203;4398](https://togithub.com/python-pillow/Pillow/issues/4398)
    [alexagv]

-   Handle multiple and malformed JPEG APP13 markers [#&#8203;4370](https://togithub.com/python-pillow/Pillow/issues/4370)
    [homm]

-   Depends: Update libwebp to 1.1.0 [#&#8203;4342](https://togithub.com/python-pillow/Pillow/issues/4342), libjpeg to 9d [#&#8203;4352](https://togithub.com/python-pillow/Pillow/issues/4352)
    [radarhere]

### [`v7.0.0`](https://togithub.com/python-pillow/Pillow/blob/master/CHANGES.rst#&#8203;700-2020-01-02)

[Compare Source](https://togithub.com/python-pillow/Pillow/compare/6.2.2...7.0.0)

-   Drop support for EOL Python 2.7 [#&#8203;4109](https://togithub.com/python-pillow/Pillow/issues/4109)
    [hugovk, radarhere, jdufresne]

-   Fix rounding error on RGB to L conversion [#&#8203;4320](https://togithub.com/python-pillow/Pillow/issues/4320)
    [homm]

-   Exif writing fixes: Rational boundaries and signed/unsigned types [#&#8203;3980](https://togithub.com/python-pillow/Pillow/issues/3980)
    [kkopachev, radarhere]

-   Allow loading of WMF images at a given DPI [#&#8203;4311](https://togithub.com/python-pillow/Pillow/issues/4311)
    [radarhere]

-   Added reduce operation [#&#8203;4251](https://togithub.com/python-pillow/Pillow/issues/4251)
    [homm]

-   Raise ValueError for io.StringIO in Image.open [#&#8203;4302](https://togithub.com/python-pillow/Pillow/issues/4302)
    [radarhere, hugovk]

-   Fix thumbnail geometry when DCT scaling is used [#&#8203;4231](https://togithub.com/python-pillow/Pillow/issues/4231)
    [homm, radarhere]

-   Use default DPI when exif provides invalid x_resolution [#&#8203;4147](https://togithub.com/python-pillow/Pillow/issues/4147)
    [beipang2, radarhere]

-   Change default resize resampling filter from NEAREST to BICUBIC [#&#8203;4255](https://togithub.com/python-pillow/Pillow/issues/4255)
    [homm]

-   Fixed black lines on upscaled images with the BOX filter [#&#8203;4278](https://togithub.com/python-pillow/Pillow/issues/4278)
    [homm]

-   Better thumbnail aspect ratio preservation [#&#8203;4256](https://togithub.com/python-pillow/Pillow/issues/4256)
    [homm]

-   Add La mode packing and unpacking [#&#8203;4248](https://togithub.com/python-pillow/Pillow/issues/4248)
    [homm]

-   Include tests in coverage reports [#&#8203;4173](https://togithub.com/python-pillow/Pillow/issues/4173)
    [hugovk]

-   Handle broken Photoshop data [#&#8203;4239](https://togithub.com/python-pillow/Pillow/issues/4239)
    [radarhere]

-   Raise a specific exception if no data is found for an MPO frame [#&#8203;4240](https://togithub.com/python-pillow/Pillow/issues/4240)
    [radarhere]

-   Fix Unicode support for PyPy [#&#8203;4145](https://togithub.com/python-pillow/Pillow/issues/4145)
    [nulano]

-   Added UnidentifiedImageError [#&#8203;4182](https://togithub.com/python-pillow/Pillow/issues/4182)
    [radarhere, hugovk]

-   Remove deprecated **version** from plugins [#&#8203;4197](https://togithub.com/python-pillow/Pillow/issues/4197)
    [hugovk, radarhere]

-   Fixed freeing unallocated pointer when resizing with height too large [#&#8203;4116](https://togithub.com/python-pillow/Pillow/issues/4116)
    [radarhere]

-   Copy info in Image.transform [#&#8203;4128](https://togithub.com/python-pillow/Pillow/issues/4128)
    [radarhere]

-   Corrected DdsImagePlugin setting info gamma [#&#8203;4171](https://togithub.com/python-pillow/Pillow/issues/4171)
    [radarhere]

-   Depends: Update libtiff to 4.1.0 [#&#8203;4195](https://togithub.com/python-pillow/Pillow/issues/4195), Tk Tcl to 8.6.10 [#&#8203;4229](https://togithub.com/python-pillow/Pillow/issues/4229), libimagequant to 2.12.6 [#&#8203;4318](https://togithub.com/python-pillow/Pillow/issues/4318)
    [radarhere]

-   Improve handling of file resources [#&#8203;3577](https://togithub.com/python-pillow/Pillow/issues/3577)
    [jdufresne]

-   Removed CI testing of Fedora 29 [#&#8203;4165](https://togithub.com/python-pillow/Pillow/issues/4165)
    [hugovk]

-   Added pypy3 to tox envlist [#&#8203;4137](https://togithub.com/python-pillow/Pillow/issues/4137)
    [jdufresne]

-   Drop support for EOL PyQt4 and PySide [#&#8203;4108](https://togithub.com/python-pillow/Pillow/issues/4108)
    [hugovk, radarhere]

-   Removed deprecated setting of TIFF image sizes [#&#8203;4114](https://togithub.com/python-pillow/Pillow/issues/4114)
    [radarhere]

-   Removed deprecated PILLOW_VERSION [#&#8203;4107](https://togithub.com/python-pillow/Pillow/issues/4107)
    [hugovk]

-   Changed default frombuffer raw decoder args [#&#8203;1730](https://togithub.com/python-pillow/Pillow/issues/1730)
    [radarhere]

</details>

---

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appengine/flexible/scipy/requirements.txt

@@ -2,4 +2,4 @@ Flask==1.1.1
 gunicorn==20.0.4
 numpy==1.18.2
 scipy==1.2.0
-pillow==6.2.2
+pillow==7.1.0

vision/cloud-client/crop_hints/requirements.txt

@@ -1,2 +1,2 @@
 google-cloud-vision==0.42.0
-pillow==6.2.2
+pillow==7.1.0

vision/cloud-client/document_text/requirements.txt

@@ -1,2 +1,2 @@
 google-cloud-vision==0.42.0
-pillow==6.2.2
+pillow==7.1.0

vision/cloud-client/face_detection/requirements.txt

@@ -1,2 +1,2 @@
 google-cloud-vision==0.42.0
-pillow==6.2.2
+pillow==7.1.0