Enable immutable releases

[ericcornelissen]

What would you like to be added?

This action should enable immutable releases.

Why is this needed?

To help protect users against potential attacks such as GHSA-mrrh-fwg8-r2c3 by preventing re-pointing (released) tags to different commits.

[eternaltyro]

Please enable immutable releases so we can be assured that the tags can't be modified unexpectedly to point to a different commit SHA. Helps with compliance.