Fix dependency to only allow codemirror 5.

package.json

@@ -30,7 +30,7 @@
     "@ambers/contrib-web": ">=0.7.3",
     "@ambers/lang": ">0.29.1",
     "bootstrap": "^3.3.7",
-    "codemirror": ">=5.44.0",
+    "codemirror": "^5.44.0",
     "es6-promise": "^4.2.4",
     "jquery-ui-dist": ">=1.9.2",
     "require-css": "^0.1.10",