Run diff-cover as a pytest plugin

[zzzevaka]

Hey developers! Thanks for the great tool.

Currently, using diff-cover requires editing CI scripts. Have you considered including a plugin for pytest to simplify integration? I'd like to have an interface like: pytest --cov-report=xml --diff-cover-compare-branch=master --diff-cover-fail-under=100.

Does this sound useful to you, and would you consider including it as an optional plugin in diff-cover?

[kingbuzzman]

I'm not going to lie.. I like this.. I'll mull this over

[Bachmann1234]

like most things if someone wants to build it id merge it in.