ci: pre-commit updates

[vbarua]

• use flake8 from github
• update pre-commit hooks

[vbarua]

Pulling the flake8 pre-commit hook from gitlab means that users need to authenticate with gitlab when installing it:

➜  substrait git:(main) pre-commit run
[INFO] Initializing environment for https://gitlab.com/pycqa/flake8.
Username for 'https://gitlab.com': 

If we pull it from github, there's no need for authentication

➜  substrait git:(vbarua/pre-commit-updates) ✗ git commit -am "chore: pre-commit autoupdate"
[INFO] Installing environment for https://github.com/psf/black.

While I was touching the pre-commit hooks I updated them and ran them over the whole repo.

[vbarua]

These changes only affects CI and as such can be merged with only commiter approval. Thanks David!