Changelog/2020/July 21

As always, these are changes that happened since the last changelog was posted.
Bug Fixes
* Fixed being asked to and being unable to approve your own invitation when trying to /coopadd a player to a solo profile
* Fixed an exploit with the anvil menu
* Fixed an issue that caused players to get a kick error when trying to join SkyBlock
* Fixed some double tall slabs dropping null blocks when broken with Silk Touch
* Fixed being able to combine items in the anvil that aren't normally able to be enchanted
* Added a check that deletes null items automatically
* Fixed two issues with Brewing Stands