Retire plugincompat

[nicoddemus]

This website was an excellent learning tool, and provides a nice list of all pytest plugins available.

It however implements a non-trivial workflow and maintaining the website has a non-zero cost in time.

The compatibility testing done here is not really useful in the end (#39), it seems the most useful thing about the website is the list of plugins, which we now have in the pytest documentation itself:

https://docs.pytest.org/en/latest/reference/plugin_list.html

Other than that, there is a number of issues/improvements/fixes that are interesting but I don't really have the time to tackle:

• False positives when using the Framework :: Pytest classifier: Try to weed out "Framework :: Pytest" false-positives #53.

• JSON API support (Migrate from xmlrpc to PyPIJSON #61)

• Other enhancements/fixes: Add guide on how to run flask app locally for development #54, List the tox environments for each package instead of assuming 'py27' and 'py37' exist #38, Use tox in verbose mode #11, Show if test status was obtained from a real tox or a fake one #7

I don't really see the point in evolving the website any further given that the official plugin list now exists and provides a good overview of the plugin ecosystem.

Thanks for all the contributors, every help was highly appreciated!