Fix invalid escape sequence warning in Python 3.12

[oshiteku]

When importing bitsandbytes for the first time in Python 3.12, the following warning is displayed:

$ python -c 'import bitsandbytes'
/home/oshiteku/tmp/.venv/lib/python3.12/site-packages/bitsandbytes/cextension.py:48: SyntaxWarning: invalid escape sequence '\d'
  library_name = re.sub("cuda\d+", f"cuda{override_value}", library_name, count=1)

Changes:

• Fix invalid escape sequence in regex pattern
• Add linter configuration to check for invalid escape sequences

[github-actions]

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[matthewdouglas]

Thanks! I don't see the warning show up on my environment (Python 3.12.7, Arch Linux) but this change is sensible.