Create a CHANGES.md file

[ThomasGreiner]

Background We want to communicate changes that were made between releases in a more easily digestable way than git commit logs.

Looking through a couple popular projects on GitHub, there didn't appear to be any coherent theme in how changes should be communicated though so we got some options (see also http://keepachangelog.com/en/1.0.0/).

What to change Create a CHANGES.md file:

• Use CHANGES.md as file name (alternative: CHANGELOG.md)
• Use YYYY-MM-DD as date format (alternative: MMM D, YYYY)
• Group changes under "Added", "Changed", "Fixed" and "Removed" according to keepachangelog.com (alternative: group by components)
• Use issue numbers and links to tag diffs to provide more context (alternative: use commit or PR numbers)