Painting Variant Sprites

Added support for the Dennis painting introduced in 1.21.7

Added explicit support for 1.21.6, no other changes. The previous pack should continue to work if you already downloaded it.

Official release for 1.21.5

Extended explicit supported versions to include pack format 51 for 25w06a. Other than this, it is identical to the initial release.

I probably won't do this again for further snapshots up to release unless a breaking change comes up, which seems unlikely as of right now. The pack should continue to work in future snapshots up to release otherwise. I will upload an official 1.21.5 version once the drop releases.

Initial release