Make compatible with XP 11

Author: thekid

composer.json

@@ -6,7 +6,7 @@
   "description" : "Big number handling",
   "keywords": ["module", "xp"],
   "require" : {
-    "xp-framework/core": "^10.0 | ^9.0 | ^8.0 | ^7.0",
+    "xp-framework/core": "^11.0 | ^10.0 | ^9.0 | ^8.0 | ^7.0",
     "php" : ">=7.0.0"
   },
   "require-dev" : {