Fix documentation deployment, update GHA

[nefrathenrici]

This may fix the issue with the docs not deploying properly, I am not quite sure. Content

• Updates the checkout action
• Forces docs action on main branch

[codecov[bot]]

Codecov Report

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

Comparison is base (7cb2ec3) 98.50% compared to head (2308e12) 98.50%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #177 +/- ## ======================================= Coverage 98.50% 98.50% ======================================= Files 2 2 Lines 134 134 ======================================= Hits 132 132 Misses 2 2 ```

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