Add flake8 and isort to .pre-commit-config.yaml

This adds flake8 and isort to .pre-commit-config.yaml.  This way, they
will automatically be run on commit.

I chose the most recent available versions after verifying that they
don't cause any reports or changes in the current tree.

Internally at AdaCore, we also use a few flake8 plugins as well, so
perhaps that's another avenue for investigation.

v2: Also update the various file-selection clauses to pick up
gdb-gdb.py.in; include the isort change made to this file; and finally
add a comment about the exclusions from flake8.

Approved-By: Simon Marchi <simon.marchi@efficios.com>


2 files changed