Update to 1.21

[Earthcomputer]

[polarbub]

Thanks for your PR!

Due to my attempts to optimize the mod it has a tendency to get the height of structures wrong. I removed a few steps from generation that seem to be unnecessary for structure bounding box location, but for 'simple' structures it caused them to be at the wrong height. Iirc the term simple comes from somewhere in yarn. It has something to do with the structure being defined in code rather than json. Think shipwrecks or swamp huts instead of mineshafts. I removed the step where the blocks of the structure were placed, but for many 'simple' structures the bounding box is also moved to is final location in that step. I fixed this by copying and pasting the just the code that moves the bounding box for the structures that needed it, but the skipped steps would also cause random's state to be wrong, so Shipwrecks, which change height randomly, were in the wrong spot and end portals' would also have the wrong number of pre-filled eyes.

Before I can merge your PR it

1. needs to be checked that the structures are in the right place. This can be done by using my FindStuctureMoves mod on a Vanilla world and one with the Protosky mod and observing the difference in locations.
2. needs to have a fly around done in creative to make sure that there are no random blocks hanging out that shouldn't be there

Also I think that Matty (one the skytech admins) is working on redoing the mod because my version isn't 1:1 with vanilla and is kind of annoying to maintain. He is making it configurable and actually be correct. Work on that is supposedly done, but just needs testing and has been in that state for a few months, so that might be a better base to work off of then this one.

[polarbub]

I remembered that I made a release checklist at some point. Please use this one, not the one in the previous comment. To check before releasing:

• Blocks are deleted
  • Geodes tend to have issues
• End portals generate
• End cities
  • Shulkers
  • Elytra
• End pillars
• Exit end portal
• Dragon fight works
• Structure bounding boxes in the same place as Vanilla
  • Overworld
  • End
  • Nether
• Entity placement skipping (Entities don't get generated in structures and then fall into the void0
• Heightmaps are correct
  • in void
  • On structures
• Light Deleting (Lava would cause "light" suppression in some places)