Bump version to 1.5.1 (facebookincubator#1755) 

Update version to 1.5.0 (and drop support for Python 3.6 and 3.7) (fa… …cebookincubator#1752)

Update version tag to 1.4.6 for release (facebookincubator#1743) 

bump pylint 

Revert to using USR2 ("cleaner" option) (facebookincubator#1702) 

Tag 1.4.2 

Tag 1.3.0 

Tag 1.2.1 

Tag 1.2.0