Puppet Forge release 2.0.0

  Marks the commit that the branch stable/grizzly and the 2.0.0 tag is
  cut from, adds the pkg directory to .gitignore to prevent accidental
  committing of Forge artifacts to the repository, and updates release
  notes.

Change-Id: I406eb52de27b95378e498d65deaab3991999bacd