chore: release 1.3.1 (googleapis#41)

🤖 I have created a release \*beep\* \*boop\* 
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### [1.3.1](https://www.github.com/googleapis/python-pubsub/compare/v1.3.0...v1.3.1) (2020-02-28)


### Bug Fixes

* shutdown error on streaming pull callback error ([googleapis#40](https://www.github.com/googleapis/python-pubsub/issues/40)) ([552539e](https://www.github.com/googleapis/python-pubsub/commit/552539e7beb30833c39dd29bfcb0183a07895f97))
---


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

chore: release 1.3.0 (googleapis#27)

* updated CHANGELOG.md [ci skip]

* updated setup.py [ci skip]

chore: release 1.2.0 (googleapis#24)

* updated CHANGELOG.md [ci skip]

* updated setup.py [ci skip]

chore(pubsub): release 1.1.0 (#9950)

* Release 1.1.0

* Fix commit message formatting. Change version from 1.0.3 to 1.1.0 because the stop method was added to the publisher client.

chore(pubsub): release 1.0.2 (#9362)

* chore(pubsub): release 1.0.2

* Adjust release notes wording and grammar.

chore(pubsub): release PubSub 1.0.1 (#9331)

* Release PubSub 1.0.1

Release PubSub 1.0.0 (#9145)

* Release 1.0.0

* Update CPS Python library READMEs to indicate the library is now GA. Also add some extra notes about versioning and contributions.

* Fix badge image

* Fix rst docs

* Address comments by Peter and Bu Sun

* Update repo metadata

* Improve changelog entry

Release pubsub 0.45.0 (#8839)

* Release 0.45.0

* Remove redundant PubSub prefix from changelog item

Release 0.44.0 (#8804)

Release 0.43.0 (#8761)