This commit essentially adds back tests to our CI pipeline. They were
previously dropped due to Travis pricing policy change.
This workflow utilizes a few interesting projects to make this action
easier to maintain such as the codecov github action
and the tox-gh-actions project
(https://github.com/ymyzk/tox-gh-actions)
This commit uses codecov instead of coveralls because using coveralls
directly inside GH-actions is buggy and the official coveralls action
only supports lcov reports which we can't seem to be able to generate at
the moment. For more information see the pull request that introduced
this commit
Review dog is an incredible project that makes linting and formatting
review a breeze by commenting inline what is wrong in a pull request.
This makes the review process easier for the maintainer and also
provides a clearer feedback to the contributor
