chore(main): release 3.21.0 (#812)

Co-authored-by: release-please[bot] <55107282+release-please[bot]@users.noreply.github.com>

Author: release-please[bot]

CHANGELOG.md

@@ -4,6 +4,13 @@
 
 [1]: https://pypi.org/project/google-cloud-spanner/#history
 
+## [3.21.0](https://github.com/googleapis/python-spanner/compare/v3.20.0...v3.21.0) (2022-09-16)
+
+
+### Features
+
+* Add custom instance config operations ([#810](https://github.com/googleapis/python-spanner/issues/810)) ([f07333f](https://github.com/googleapis/python-spanner/commit/f07333fb7238e79b32f480a8c82c61fc2fb26dee))
+
 ## [3.20.0](https://github.com/googleapis/python-spanner/compare/v3.19.0...v3.20.0) (2022-08-30)
 
 

setup.py

@@ -22,7 +22,7 @@
 
 name = "google-cloud-spanner"
 description = "Cloud Spanner API client library"
-version = "3.20.0"
+version = "3.21.0"
 # Should be one of:
 # 'Development Status :: 3 - Alpha'
 # 'Development Status :: 4 - Beta'