Merged requested to merge bitbucket/merged-pr-368 into branch/3.0
Created originally on Bitbucket by martey (Martey Dodoo)
Was already merged in Bitbucket before import, marked as merged by the import user
Update changelog to make it clearer that version 2.6.4 is the last version that supports Python 3.5, and that 3.x.x only supports Python 3.6 and above. This should reduce confusion for users still on Python 3.5 (see #1364 (closed) and #1402 (closed)).