Release date for 1.4.9

Travis: temporarily disable Python 3.8

There seems to be a compatibility error in Werkzeug on the prerelease of
3.8.

Don't require python2 for releases

Release date for 1.4.6

Add date to changelog

Add date to the changelog

Add 1.4.3 release date

Add date to changelog

Change released version to 1.4.1

Sadly, I uploaded the wrong file to PyPI for 1.4.0. Once you do this, PyPI
never lets you change the file associated with a given released version. So we
need to use 1.4.1 instead. 😢

Add release date for 1.3.19