Retiring in favor of coverage lcov

[TheCleric]

coveragepy has had lcov support for some time now (see https://coverage.readthedocs.io/en/latest/cmd.html#cmd-lcov), and its support extends back to python 3.7. Considering that I think that having it integrated within the tool (instead of this library working as a bridge) is a better solution, and our python 3.6 support is for a release that has been out of support for 2.5 years, I think it's time to retire this repo.

If anyone has any objections, feel free to comment here. To be clear, the pip packages would remain up at PyPi, just no new development going forward.