Update package.json

package.json

@@ -16,6 +16,6 @@
     "firefox": ">=38.0a1",
     "fennec": ">=38.0a1",
     "seamonkey": ">=2.0a1 <=2.46",
-    "{8de7fcbb-c55c-4fbe-bfc5-fc555c87dbc4}": ">=27.1.0b1"
+    "{8de7fcbb-c55c-4fbe-bfc5-fc555c87dbc4}": ">=27.1.0b1 <=28.*"
   }
 }