Updated Upstream (CraftBukkit)

Upstream has released updates that appear to apply and compile correctly.
This update has not been tested by PaperMC and as with ANY update, please do your own testing

CraftBukkit Changes:
b5d7883a SPIGOT-6634: Override needed method
99561c21 SPIGOT-6624: Explosions do not destroy blocks out of vanilla heights in custom dimensions

patches/server/MC-Utils.patch

@@ -4257,7 +4257,7 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 +++ b/src/main/java/org/bukkit/craftbukkit/util/DummyGeneratorAccess.java
 @@ -0,0 +0,0 @@ public class DummyGeneratorAccess implements LevelAccessor {
      public FluidState getFluidState(BlockPos pos) {
-         throw new UnsupportedOperationException("Not supported yet.");
+         return Fluids.EMPTY.defaultFluidState(); // SPIGOT-6634
      }
 +    // Paper start - if loaded util
 +    @javax.annotation.Nullable