update github actions

[maurerle]

This fixes the following warning on our runs:

Node.js 16 actions are deprecated. Please update the following actions to use Node.js 20: actions/checkout@v3, actions/setup-python@v4, actions/upload-artifact@v3. For more information see: https://github.blog/changelog/2023-09-22-github-actions-transitioning-from-node-16-to-node-20/.

[codecov[bot]]

Codecov Report

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

Comparison is base (0969c35) 77.09% compared to head (bef18ab) 77.09%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #296 +/- ## ======================================= Coverage 77.09% 77.09% ======================================= Files 41 41 Lines 4689 4689 ======================================= Hits 3615 3615 Misses 1074 1074 ``` | [Flag](https://app.codecov.io/gh/assume-framework/assume/pull/296/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=assume-framework) | Coverage Δ | | |---|---|---| | [pytest](https://app.codecov.io/gh/assume-framework/assume/pull/296/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=assume-framework) | `77.09% <ø> (ø)` | | 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=assume-framework#carryforward-flags-in-the-pull-request-comment) to find out more.

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