chore: Bump version to 6.1.6

fix: Add content type to package long description

This will allow the package to be uploaded to pypi, as it was failing
checks.

chore: Bump version to 6.1.4

docs: Add 6.1.3 notes in CHANGES

update CHANAGES.rst with the latest fixes.

chore: Bump to v6.1.1

chore: Bump to v6.1.0

Fix .rst lint

5.2.0 version bump.

Another package that dropped 3.3 compatibility.