Grave Destruction fix for "You're in Grave Danger" and "L_Ender 's Cataclysm" bosses

I love the Cataclysm mod by L_Ender and I love the You're In Grave Danger mod by b1n_ry.

Sadly, the Cataclysm bosses are able to destroy the graves from YIGD, and that is a problem when running a server. If you play alone, you can just use console commands to restore graves, but less so for players on a server without operator permissions. Thus, with a LOT of help from b1n_ry(he basically told me exactly what to do, I just typed some stuff after that, 90% credit goes to him for this), I put together this little data pack that adds the grave tag from YIGD to the files from Cataclysm that define which blocks are immune to the bosses. 

 I tested this on the Netherite Monstrosity, but the process is the same for all the bosses, so I see no reason it shouldn't also work on the others. 

Let me know if this causes any issues