chore: release 1.9.1 (#932)

:robot: I have created a release \*beep\* \*boop\* 
---
### [1.9.1](https://www.github.com/googleapis/google-api-python-client/compare/v1.9.0...v1.9.1) (2020-06-02)


### Bug Fixes

* fix python-api-core dependency issue ([#931](https://www.github.com/googleapis/google-api-python-client/issues/931)) ([42028ed](https://www.github.com/googleapis/google-api-python-client/commit/42028ed2b2be47f85b70eb813185264f1f573d01))
---


This PR was generated with [Release Please](https://github.com/googleapis/release-please).
diff --git a/setup.py b/setup.py
index f15ae37..6331a49 100644
--- a/setup.py
+++ b/setup.py
@@ -52,7 +52,7 @@
 with io.open(readme_filename, encoding="utf-8") as readme_file:
     readme = readme_file.read()
 
-version = "1.9.0"
+version = "1.9.1"
 
 setup(
     name="google-api-python-client",