1.21.3 support

[nijahplays]

title

[Felix14-v2]

This mod works just fine on 1.21.3 as it isn't restricted by version. So you can just use FastQuit 3.0.0 - 1.20.5-1.21.1

But yeah, @KingContaria could you mark the version as compatible on Modrinth, please?

[KingContaria]

The version is not fully compatible since there is a mixin crash under very specific usecases (uploading a world to realms) so I wont mark it as compatible
For most users it will just work fine tho
I wont be available to review the open update PR until sometime january