Remove XP 9, XP 8, XP 7

Author: thekid

composer.json

@@ -6,7 +6,7 @@
   "description" : "XP Compiler",
   "keywords": ["module", "xp"],
   "require" : {
-    "xp-framework/core": "^10.0 | ^9.0 | ^8.0 | ^7.0",
+    "xp-framework/core": "^11.0 | ^10.0",
     "xp-framework/ast": "^7.7",
     "php" : ">=7.0.0"
   },