Release 2.0.0

Update Mixins for 0.8.4

• Updated minVersion and compatibilityLevel in Mixin config.
• Added @mutable annotation to setters of final fields in Accessors
  to prevent IllegalAccessError.
• Removed getter for BlockStateBase#canOcclude in Accessors as vanilla
  has a getter now, and update BlockConfig.BLOCKCONFIG_BUILDER to use
  the vanilla getter.

Remove inconsequential timestamp from copyright headers
This is highly problematic to maintain in IDEA via Velocity template
since the timestamps are updated by the filesystem-specific last
modification time, and not the last time a file was changed in the
context of VCS. It becomes highly apparent when switching between
branches when different VCS objects are loaded.

Update Forge to 1.17.1 RB

• Update Forge to 37.1.0, Parchment to 2021.10.31
• Update mods.toml to lock this release to Forge 37.x since
  38.x contains refactoring that will break this mod in 1.18
• Update constant value locations to remove deprecated references.
• Fully qualify net.minecraft.tags.Tag in javadocs to prevent
  collision with net.minecraft.nbt.Tag. Thanks Mojang for identically
  naming two separate classes that could so easily collide.
• Remove redundant finals from a couple of declarations.

This should be the final and only release for 1.17 pending bugs.