Add v1.15.1 to the release notes

Update changelog for 1.15.0

Updated CHANGES for 1.14.2

Adjust classifiers to indicate Python version support

Updated tests to run against ansi2html 1.2.0

Disable ANSI codes support by default

Due to ansi2html having a less permissive license, remove it as a dependency.

Update release notes for v1.12.0

Added credits to release notes

Update release notes for 1.11.0

No need to install into flake8 environments