Add commit-message-validator to jenkins' envlist
Add commit-message-validator to jenkins' envlist

Also, use dashes instead of underscores for flake8-invalid-escape-sequences.
Apparently, it's more customary to write package names with dashes and that's
how setuptools treats them anyway.[1]

[1]: https://mail.python.org/pipermail/distutils-sig/2011-August/017936.html

Change-Id: I88d2f39fad7c6ef9a11f33b30e1be67f5dcdcafe

magul/pywikibot-core,magul/pywikibot-core,wikimedia/pywikibot-core,wikimedia/pywikibot-core,PersianWikipedia/pywikibot-core