Add paragraph about PDF code of conduct.
Attempt to fix some failing tests
Fix the PDF core fonts test
Clear rcParams better
Fix tolerance on rasterize test
Merge pull request #2367 from mdboom/fix-failing-tests

Fix a number of long-failing tests.
Partially fix #2343: Forcibly set the locale to en_US.UTF-8 during tests so that the output will match the baseline images
Merge pull request #2192 from mdboom/code-of-conduct2

Follow the PSF code of conduct
Merge pull request #2335 from andreabedini/patch-5

make sure we only perform absolute imports on loading a backend
Raise tolerance on test_rasterize_dpi
Merge pull request #2368 from mdboom/test/set-locale

Set locale for tests