upgrade Pylint 2.7.1 → 2.7.3

upgrade Pylint 2.7.1 → 2.7.3

Commit a9c626e7f6a81f0949b1e4134e17c8968f13256b cherry-picked some upcoming
Pylint changes related to inclusive terminology. This and the remainder of the
changes relevant to Graphviz (the `extension-pkg-allow-list` option) made their
way into Pylint 2.7.3. By upgrading to 2.7.3 “whitelist” terminology can be
removed from Graphviz’ Pylint configuration.

Note that a9c626e7f6a81f0949b1e4134e17c8968f13256b incorrectly quotes Pylint
commit hashes from PR3961¹ that never made their way into the main Pylint branch
as-is but were rebased. The corresponding commit hashes are:

  * 850c442dbda8d332049971d5c38f82b86da44f1d became
    d19c7733717ae9ad0a527233c2950473dce3ffcf
  * 12a76469782fab5c23d78039c4bfb37e3331945a became
    12beaa0d3fa050b68dff092520966c63d2f0e437

¹ https://github.com/PyCQA/pylint/pull/3961