Bumped version to 2.15.1 (firebase#253)

Bumped version to 2.15.0 (firebase#251)

* Bumped version to 2.15.0

* Updated changelog

Bumped version to 2.14.0 (firebase#230)

Bumped version to 2.13.0 (firebase#194)

Bumped version to 2.12.0 (firebase#181)

* Bumped version to 2.12.0

* Updated changelog

Bumped version to 2.11.0 (firebase#174)

* Bumped version to 2.11.0

* Removing redundant whitespace

Bumped version to 2.10.0 (firebase#153)

 Bumped version to 2.9.1 (firebase#137)

* Bumped version to 2.9.1

* Changlog updates

* Changlog url

* trigger cla check

Bumped version to 2.9.0 (firebase#129)

Bumped version to 2.8.0 (firebase#116)