ci: add pr trigger types

[beeme1mr]

This PR

• adds pr trigger types
• removes changes to main trigger

Notes

This should trigger a CI run for a release PR.

https://github.com/open-feature/python-sdk-contrib/pull/40

[codecov[bot]]

Codecov Report

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

Comparison is base (d8e10c7) 90.55% compared to head (ab5fb31) 90.55%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #41 +/- ## ======================================= Coverage 90.55% 90.55% ======================================= Files 8 8 Lines 180 180 ======================================= Hits 163 163 Misses 17 17 ``` | [Flag](https://app.codecov.io/gh/open-feature/python-sdk-contrib/pull/41/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=open-feature) | Coverage Δ | | |---|---|---| | [unittests](https://app.codecov.io/gh/open-feature/python-sdk-contrib/pull/41/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=open-feature) | `90.55% <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=open-feature#carryforward-flags-in-the-pull-request-comment) to find out more.

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[beeme1mr]

Side note: We should make @gruebel an approver. I'll open a PR for that in a moment.

[federicobond]

I was about to do just that ❤️