1.21.5 (#51)

* update beet

* update generated files

* remove observer overlays

* bump minor version for worldgen

* flatten overlays

- can't sustainably provide backwards compat at the moment

* update root advancement background

* update all dependencies

* update tellraws to SNBT

* nbt changes

* equipment nbt

* update wandering traders

* update piglin bartering

* add resin clump to wandering trader

* add music disc creator music box to ominous vaults

* add bush to wandering trader

* fix standard island load check

* fix gm4_trades function tags

* make sand island postgen

- allows the island to actually generate from worldspawn

* add sand island into standard skyblock bundle

* add ward armor trim to HotV gift

* update additions README

* update sand island README

* bump version numbers

* fix piglin bartering loot table

- remove dried ghast cuz that's 1.21.6

* fix witch and zombie boat advancements

* fix knockback resistance

* fix vanilla oneblock starter weather (again)

actually fixed this time

* set weather gamerule when forced stopped

* bring player down to 2 hearts upon first starve damage

* bump minor of vanilla oneblock starter

* build release files

* fix spore blossom moss bug

Author: BPR02