chore: release 2.0.0

Author: release-please[bot]

CHANGELOG.md

@@ -4,6 +4,17 @@
 
 [1]: https://pypi.org/project/google-cloud-spanner/#history
 
+## [2.0.0](https://www.github.com/googleapis/python-spanner/compare/v1.19.1...v2.0.0) (2020-11-11)
+
+
+### ⚠ BREAKING CHANGES
+
+* migrate to v2.0.0 (#147)
+
+### Features
+
+* migrate to v2.0.0 ([#147](https://www.github.com/googleapis/python-spanner/issues/147)) ([bf4b278](https://www.github.com/googleapis/python-spanner/commit/bf4b27827494e3dc33b1e4333dfe147a36a486b3))
+
 ### [1.19.1](https://www.github.com/googleapis/python-spanner/compare/v1.19.0...v1.19.1) (2020-10-13)