Add Python 3.12

[codecov[bot]]

Codecov Report

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

Comparison is base (e668e6f) 85.44% compared to head (c953946) 85.45%. Report is 1 commits behind head on master.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #508 +/- ## ======================================= Coverage 85.44% 85.45% ======================================= Files 31 31 Lines 1834 1842 +8 Branches 207 231 +24 ======================================= + Hits 1567 1574 +7 Misses 188 188 - Partials 79 80 +1 ``` | [Flag](https://app.codecov.io/gh/aio-libs/aiohttp-debugtoolbar/pull/508/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=aio-libs) | Coverage Δ | | |---|---|---| | [unit](https://app.codecov.io/gh/aio-libs/aiohttp-debugtoolbar/pull/508/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=aio-libs) | `85.28% <100.00%> (+<0.01%)` | :arrow_up: | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=aio-libs#carryforward-flags-in-the-pull-request-comment) to find out more.

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[Dreamsorcerer]

3.12:

3.10: