Fix SyntaxWarning with Python 3.12

[sryze]

Description

When using Python 3.12, e.g. when installing via Homebrew with the latest Python installed, I get this warning:

pgspecial/main.py:237: SyntaxWarning: invalid escape sequence '\w'

It also displays every time I run pgcli --version.

Checklist

• [ ] I've added this contribution to the changelog.rst.
• [ ] I installed pre-commit hooks (pip install pre-commit && pre-commit install), and ran black on my code.
• [x] Please squash merge this pull request (uncheck if you'd like us to merge as multiple commits)

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

:exclamation: No coverage uploaded for pull request base (main@b3abb95). Click here to learn what that means.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #145 +/- ## ======================================= Coverage ? 67.45% ======================================= Files ? 6 Lines ? 1220 Branches ? 0 ======================================= Hits ? 823 Misses ? 397 Partials ? 0 ```

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[j-bennet]

👍 thank you @sryze , nice catch.