Recent Commits to Mastodon.py:master

replace pytest-vcr with pytest-recording in docs

replace pytest-vcr dependency with pytest-recording

The former is unmaintained upstream.

Fixes: https://github.com/halcy/Mastodon.py/issues/406

fix compatibility with pytest-recording

pytest-recording stores cassettes for each module in its own directory.
Using "vcr_cassette_dir" fixture, we override it to use the old
behavior.