chore(main): release 3.20.0 (#790)

🤖 I have created a release *beep* *boop*
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## [3.20.0](v3.19.0...v3.20.0) (2022-08-30)


### Features

* Adds TypeAnnotationCode PG_JSONB ([#792](#792)) ([6a661d4](6a661d4))


### Bug Fixes

* if JsonObject serialized to None then return `null_value` instead of `string_value` ([#771](#771)) ([82170b5](82170b5))

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

Author: release-please[bot]

CHANGELOG.md

@@ -4,6 +4,18 @@
 
 [1]: https://pypi.org/project/google-cloud-spanner/#history
 
+## [3.20.0](https://github.com/googleapis/python-spanner/compare/v3.19.0...v3.20.0) (2022-08-30)
+
+
+### Features
+
+* Adds TypeAnnotationCode PG_JSONB ([#792](https://github.com/googleapis/python-spanner/issues/792)) ([6a661d4](https://github.com/googleapis/python-spanner/commit/6a661d4492bcb77abee60095ffc2cfdc06b48124))
+
+
+### Bug Fixes
+
+* if JsonObject serialized to None then return `null_value` instead of `string_value` ([#771](https://github.com/googleapis/python-spanner/issues/771)) ([82170b5](https://github.com/googleapis/python-spanner/commit/82170b521f0da1ba5aaf064ba9ee50c74fe21a86))
+
 ## [3.19.0](https://github.com/googleapis/python-spanner/compare/v3.18.0...v3.19.0) (2022-08-17)
 
 

setup.py

@@ -22,7 +22,7 @@
 
 name = "google-cloud-spanner"
 description = "Cloud Spanner API client library"
-version = "3.19.0"
+version = "3.20.0"
 # Should be one of:
 # 'Development Status :: 3 - Alpha'
 # 'Development Status :: 4 - Beta'