Support using built-in tomllib in Python 3.11

[codecov-commenter]

Codecov Report

Base: 97.86% // Head: 97.82% // Decreases project coverage by -0.04% :warning:

Coverage data is based on head (1f74c0b) compared to base (74fd023). Patch coverage: 80.00% of modified lines in pull request are covered.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #654 +/- ## ========================================== - Coverage 97.86% 97.82% -0.05% ========================================== Files 1 1 Lines 2391 2393 +2 ========================================== + Hits 2340 2341 +1 - Misses 51 52 +1 ``` | [Impacted Files](https://codecov.io/gh/hhatto/autopep8/pull/654?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Hideo+Hattori) | Coverage Δ | | |---|---|---| | [autopep8.py](https://codecov.io/gh/hhatto/autopep8/pull/654/diff?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Hideo+Hattori#diff-YXV0b3BlcDgucHk=) | `97.82% <80.00%> (-0.05%)` | :arrow_down: | Help us with your feedback. Take ten seconds to tell us [how you rate us](https://about.codecov.io/nps?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Hideo+Hattori). Have a feature suggestion? [Share it here.](https://app.codecov.io/gh/feedback/?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Hideo+Hattori)

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[hhatto]

thanks 👍

[mgorny]

Thanks a lot!