Fix `3.x` release pipeline

[chippmann]

Fixes #467

Also drops the update docs workflow and fixes the version regex (now the editor assets should have the correct release version in their name again). This also fixes the name inconsistencies between the editor builds per platform. They have now all the same prefix.

For a test release see: https://github.com/chippmann/godot-kotlin-jvm/releases/tag/0.6.1-3.5.2

Note: The following things need to also go into master:

• name inconsistency fix for editor builds
• regex fix

For these I will submit a separate PR in the near future.

[chippmann]

The failing check is because of the gpg key not being accessible for forks.