pyupgrade is a tool (and pre-commit hook) to automatically upgrade
syntax for newer versions of the language. It helps getting rid of
syntax required for older python versions not supported anymore and
prepare us for easier support of newer python versions. The tool is
already used in some other OpenStack projects, so it is time to start
using it also for Keystone.
The change is generated by uncommenting the pre-commit hook and
executing `pre-commit run -a` to convert the data. The same could be
also achieved by simply trying to commit and adding converted files in
few iterations.
Change-Id: Ia1f64709e57ebb4e44db128bfea4c5957b2071df
aaf0cc8fae