Fix GitHub Actions deprecations and warnings

[JOJ0]

Fixes #133

[JOJ0]

Sorry @JacksonChen666, not really ready for review. Just desperately trying to trigger the release workflow. As I understood it, it should be sufficient to push a tag named v* to trigger it. But it doesn't seem to work...Hmm 🤔

[JOJ0]

Ok got it, retag.sh helped to remind me on how to trigger/test all this.

Now it's ready to review. Note that in this case the failed release workflow is a good thing. It tells us that the workflow is running as planned triggered via my test-tag-push (v0.46.2) and at least this "early exit" on version mismatch is doing its job correctly:

(Now deleted test tag v0.46.2 again)

As far as I can see all the deprecations as documented in the screenshot in #133 (headline "Annotations") are gone, but please double check!

[JacksonChen666]

For the most part, seems fine.

I tried testing changes in my own repo (can't be a fork because... reasons¹). It didn't work and spit the error Resource not accessible by integration, implying that permissions are needed, but since releases worked on JOJ0/synadm already (for whatever reason), I'm just gonna assume it's gonna work as well.

Footnotes

1. See error on https://github.com/JacksonChen666/synadm/actions/runs/10788162806 ↩

[JOJ0]

Thanks for testing! Seems fine!