[google_maps_flutter] update ios privacy manifest (flutter#6511)

The installation instructions for Google Maps Platform SDKs for iOS now have download links and instructions for **manually** adding Privacy Manifest files for use with the latest versions of the SDKs. You can read more about this [here](googlemaps/google-maps-ios-utils#463 (comment)).

This PR synchronizes the iOS privacy manifest with the file provided by Google for the Maps SDK for iOS. 
The privacy manifest was downloaded from: [https://developers.google.com/maps/documentation/ios-sdk/config#add-apple-privacy-manifest-file](https://developers.google.com/maps/documentation/ios-sdk/config#add-apple-privacy-manifest-file).

As you can see in the new **[PrivacyInfo.xcprivacy](packages/google_maps_flutter/google_maps_flutter_ios/ios/Resources/PrivacyInfo.xcprivacy)** file Google Maps SDK is using the following **NSPrivacyAccessedAPITypes**:

- **NSPrivacyAccessedAPICategoryDiskSpace**
- **NSPrivacyAccessedAPICategorySystemBootTime**
- **NSPrivacyAccessedAPICategoryFileTimestamp**
- **NSPrivacyAccessedAPICategoryUserDefaults**

*Related issues:*
- [flutter/flutter/issues/145269](flutter/flutter#145269)
- [flutter/flutter/issues/143232](flutter/flutter#143232)
- [flutter/flutter/issues/131940](flutter/flutter#131940 (comment))

Fixes flutter/flutter#94491

Author: rrpadilla

packages/google_maps_flutter/google_maps_flutter_ios/CHANGELOG.md

@@ -1,3 +1,15 @@
+## 2.6.0
+
+* Updates the minimum allowed verison of the Google Maps SDK to 8.4, for privacy
+  manifest support.
+    * This means that applications using this package can no longer support
+      iOS 13 or 14, as the versions of the Google Maps SDK that support those
+      versions do not have privacy manifests, so cannot be used in published
+      applications once the new App Store enforcement of manifests takes effect.
+* Includes the Google Maps SDK's [GoogleMapsPrivacy bundle](https://developers.google.com/maps/documentation/ios-sdk/config#add-apple-privacy-manifest-file)
+  manifest entries direct in the plugin, so that package clients do not need to
+  manually add that privacy bundle to the application build.
+
 ## 2.5.2
 
 * Fixes the tile overlay not correctly displaying on physical ios devices.