chore: release 1.3.1 (#98)

🤖 I have created a release \*beep\* \*boop\*
---
### [1.3.1](https://www.github.com/googleapis/python-billing/compare/v1.3.0...v1.3.1) (2021-07-20)


### Bug Fixes

* **deps:** pin 'google-{api,cloud}-core', 'google-auth' to allow 2.x versions ([#96](https://www.github.com/googleapis/python-billing/issues/96)) ([a9e5368](https://www.github.com/googleapis/python-billing/commit/a9e536849aea8fe4ba513cd5503c275c4a7db880))
---


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]

packages/google-cloud-billing/CHANGELOG.md

@@ -1,5 +1,12 @@
 # Changelog
 
+### [1.3.1](https://www.github.com/googleapis/python-billing/compare/v1.3.0...v1.3.1) (2021-07-20)
+
+
+### Bug Fixes
+
+* **deps:** pin 'google-{api,cloud}-core', 'google-auth' to allow 2.x versions ([#96](https://www.github.com/googleapis/python-billing/issues/96)) ([a9e5368](https://www.github.com/googleapis/python-billing/commit/a9e536849aea8fe4ba513cd5503c275c4a7db880))
+
 ## [1.3.0](https://www.github.com/googleapis/python-billing/compare/v1.2.1...v1.3.0) (2021-07-01)
 
 

packages/google-cloud-billing/setup.py

@@ -19,7 +19,7 @@
 import os
 import setuptools  # type: ignore
 
-version = "1.3.0"
+version = "1.3.1"
 
 package_root = os.path.abspath(os.path.dirname(__file__))