Make compatible with amroutine changes in V15

Author: pashkinelfe

src/rumutil.c

@@ -128,6 +128,9 @@ rumhandler(PG_FUNCTION_ARGS)
 	amroutine->ampredlocks = true;
 #if PG_VERSION_NUM >= 100000
 	amroutine->amcanparallel = false;
+#endif
+#if PG_VERSION_NUM >= 150000
+	amroutine->amhotblocking = true;
 #endif
 	amroutine->amkeytype = InvalidOid;