Adjust for newer weirdness in the python/pylama checker.

bump to version 3.0.0

bump to v2.3.0 and update changelog and credits

bump to 2.2.0 and update changelog

change to version 2.1.0

update the header comments for version 2.0.0

switch to version 1.2.0 and update the changelog

switch to version 1.1.0

switch to version 1.0.0