CHANGELOG.md does not contain 2.2.0 release information

__Steps to reproduce:__
List the minimal actions needed to reproduce the behavior.

1. Open the CHANGELOG.md in this repo, and click the link to download the file to display offline.
2. See that file only contains "unreleased" and releases from 2.1.1 backwards.
3. Sigh in disappointment

__Expected behavior:__
Expect that the CHANGELOG.md would be updated to display the changes added in the 2.2.0 release.

__Actual behavior:__
Info for release 2.2.0 was not included in the file.

__Environment info:__
n/a

__Config:__
n/a

Just another comment.. the whole "make the users download the CHANGELOG.md file and render it offline in whatever app they can find instead of committing it to github" only exacerbates the issue that the release process is neglecting to update the change log at all.