tests missing in sdist/ incoherent tagging vs tarball naming

Hi! I'm packaging python-publisuffx2 for Arch Linux and would like to be able to run tests from the sdist tarball on pypi.
Although the test files should be included (according to MANIFEST.in), they are not.

As a test I've checked out the current latest version (release-2.2019-12-21) and ran `python setup.py sdist` myself. The files are included in the created sdist tarball, which makes me wonder how the sdists for pypi.org were created.

It would be great, if the sdists included the tests, as currently I have to use the github tarballs to be able to run the tests.

This leads me to the second topic: The tag naming and resulting tarballs are incoherent and lead to more complicated string substitutions to track upstream and/or use the github source tarball vs. using pypi's sdist tarball: `release-2.2019-12-21` -> `publicsuffix2-2.20191221.tar.gz`
I understand, that the tagging scheme so far follows an ISO standard for the date, but it would be more coherent to strip the hyphens to be in line with the resulting tarball/wheel: e.g. `release-2.20191221` -> `publicsuffix2-2.20191221.tar.gz`