add --bump flag to git review command to request follow-up review

The goal of this change is to allow developers to easily notify
team members that a pull request is ready for a follow-up review by
posting a comment in github w/ a short summary of relevant changes.
bump version
update docs
add test coverage for listing merged branches
bump version
Merge branch 'review-bump'

* review-bump:
  bump version
  add test coverage for listing merged branches
  update docs
  bump version
  add --bump flag to git review command to request follow-up review