Ensure support for Python 3.11/3.12

[Jamim]

Hello @jkbrzt,

Thank you for this awesome tool! 🙇🏻‍♂️

I believe it would be nice to have supported Python versions listed explicitly, so I'd like to suggest changes that:

• enable testing for Python 3.11/3.12 on CI
• update classifiers at setup.py

Best regards!

[codecov-commenter]

Codecov Report

Attention: 315 lines in your changes are missing coverage. Please review.

Comparison is base (4d7d6b6) 97.28% compared to head (946ad3a) 94.26%. Report is 360 commits behind head on master.

Files	Patch %	Lines
httpie/output/ui/rich_help.py	52.88%	49 Missing :warning:
httpie/compat.py	36.73%	31 Missing :warning:
httpie/manager/tasks/plugins.py	79.73%	31 Missing :warning:
httpie/internal/daemons.py	48.27%	30 Missing :warning:
httpie/output/ui/rich_utils.py	0.00%	18 Missing :warning:
httpie/output/ui/man_pages.py	0.00%	16 Missing :warning:
httpie/output/ui/rich_progress.py	75.80%	15 Missing :warning:
httpie/manager/compat.py	62.85%	13 Missing :warning:
httpie/cli/argparser.py	89.02%	9 Missing :warning:
httpie/output/ui/palette.py	87.50%	9 Missing :warning:
... and 32 more

:exclamation: Your organization needs to install the Codecov GitHub app to enable full functionality.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #1540 +/- ## ========================================== - Coverage 97.28% 94.26% -3.02% ========================================== Files 67 113 +46 Lines 4235 7695 +3460 ========================================== + Hits 4120 7254 +3134 - Misses 115 441 +326 ```

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[jkbrzt]

Thanks, @Jamim!