chore: release 2.0.0 (#163)

🤖 I have created a release \*beep\* \*boop\* 
---
## [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

* DB-API driver + unit tests ([#160](https://www.github.com/googleapis/python-spanner/issues/160)) ([2493fa1](https://www.github.com/googleapis/python-spanner/commit/2493fa1725d2d613f6c064637a4e215ee66255e3))
* 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))
---


This PR was generated with [Release Please](https://github.com/googleapis/release-please).

CHANGELOG.md

@@ -4,6 +4,18 @@
 
 [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
+
+* DB-API driver + unit tests ([#160](https://www.github.com/googleapis/python-spanner/issues/160)) ([2493fa1](https://www.github.com/googleapis/python-spanner/commit/2493fa1725d2d613f6c064637a4e215ee66255e3))
+* 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)