Diff-cover

* Adds 'quiet mode' which will only print errors and failures. Flag -q thanks kasium https://github.com/Bachmann1234/diff_cover/issues/160
* Several internal improvement to tools and configs. Thanks kasium !

* Fixes a bug where clover reports were not counting conditionals (Thanks for ZSmallX providing a detailed report that made fixing this easy) (https://github.com/Bachmann1234/diff_cover/issues/190)
* Switch to github actions for CI as I ran out of free credits for travis and this job does not pay
* Drop 'official' support for pypy3. I don't really have any reason to think pypy wont work for this project and I wanted to simplify my ci builds.

* Bug fix to in include's functionality around absolute vs reletive paths (Thanks Kasium https://github.com/Bachmann1234/diff_cover/pull/187)
* Some pylint fixes (Thanks Kasium https://github.com/Bachmann1234/diff_cover/pull/186)

* Add the --includes option for diff-quality (Thanks kasium https://github.com/Bachmann1234/diff_cover/pull/184)

* Removing universal wheels as we do not support python 2 (thanks nicoddemus)
* relaxing the requirement for chardet to 3.0

* Bumping a major version as I am dropping python 3.5 support as it has been EOL for some time
* As a consolation I am adding 3.9 to the build. The project ran on 3.9 just fine (I develop on it..) but I had not declared support