Prepare for 0.15.2 release (googleapis#491)

Also, remove overview.rb from golden test manifest

prepare for 0.15.1 release (googleapis#488)

Release version 0.15.0 (googleapis#487)

Release artman 0.14.3 (googleapis#482)

* release artman v0.14.3

* release artman v0.14.3

* release artman v0.14.3

* also update setup.py with 0.14.3

Bump toolkit version (googleapis#472)

release 0.14.1 (googleapis#471)

fix auto-release (googleapis#468)