change log
1. updated textures to match the new datapack v2.4.1 textures.
2. Added 4 Wither variants; Normal, Invulnerable, Armored, Armored Invulnerable. random chance for each.
3. Added Angry Wolf
4. Updated en_US_mobnames.yml as follows:
wither:
  1: Wither Head
  2: Invulnerable Wither Head
  3: Armored Wither Head
  4: Armored Invulnerable Wither Head
wolf: Wolf Head
wolf_angry: Angry Wolf Head