don't error for (local) repos with no rev key

[jepler]

Closes: #22

Also:

• updates some required actions to non-deprecated versions
• makes the CI of this repo work again

[jepler]

After this change, running the script locally in udecimal prints

$ python /home/jepler/src/actions-ci-circuitpython-libs/print_precommit_versions.py
Using the following pre-commit hook versions:
 * https://github.com/psf/black @ 23.9.1
 * https://github.com/fsfe/reuse-tool @ v2.1.0
 * https://github.com/pre-commit/pre-commit-hooks @ v4.4.0
 * https://github.com/pycqa/pylint @ v3.0.0
 * local @ None

[jepler]

[NOW RESOLVED] The CI fails in this branch but also on main:

Directory 'actions-ci' does not exist!
CI expects the 'actions-ci-circuitpython-libs' tools being checked out to said directory.
Error: Process completed with exit code 1.

[tekktrik]

Looks good to me! I didn't consider local entries, so this is great!