Pillager Outpost Fix

This datapack fixes the two missing blocks at the top of the pillager outpost tower, which made the outpost's roof asymmetrical. It bothered me. I fixed it. Sorry, there are no versions below 1.16. There are some weird things with NBT data going on that I don't understand. This is my first datapack, sorry.

This has been on the Mojang bug tracker since June 2019, as confirmed here. MC-154097