Update CHANGELOG.md

Merge pull request #191 from github/smowton/admin/update-changelog-2.…

…20.7

Update CHANGELOG.md for release 2.20.7

Update CHANGELOG.md for 2.20.6

Add 2.20.5 to changelog

Update CHANGELOG.md for 2.20.4

Changelog for 2.20.3

Update changelog for 2.20.2

Add known issue for Windows exe properties version number

Update changelog for 2.20.0

Merge pull request #185 from github/alexet/add-change-log-2.19.4

Add changelog for 2.19.4