chore: Release v2.0.0 (#58)

* chore: release v2.0.0

* Link to migration guide in CHANGELOG

Author: plamut

packages/google-cloud-bigquery-datatransfer/CHANGELOG.md

@@ -4,6 +4,18 @@
 
 [1]: https://pypi.org/project/google-cloud-bigquery-datatransfer/#history
 
+## 2.0.0
+
+09-21-2020 08:36 PDT
+
+
+### Implementation Changes
+
+- Transition the library to microgenerator. ([#56](https://github.com/googleapis/python-bigquery-datatransfer/pull/56))
+  This is a **breaking change** that introduces several **method signature changes** and **drops support
+  for Python 2.7 and 3.5**. See [migration guide](https://googleapis.dev/python/bigquerydatatransfer/latest/UPGRADING.html)
+  for more info.
+
 ## 1.1.1
 
 09-16-2020 11:12 PDT