updated forum to require v2.0.0 of the markdown plugin

package.json

@@ -41,7 +41,7 @@
     "nconf": "~0.7.1",
     "nodebb-plugin-dbsearch": "^0.2.1",
     "nodebb-plugin-emoji-extended": "^0.4.1-4",
-    "nodebb-plugin-markdown": "^1.0.0",
+    "nodebb-plugin-markdown": "^2.0.0",
     "nodebb-plugin-mentions": "^0.11.0",
     "nodebb-plugin-soundpack-default": "~0.1.1",
     "nodebb-plugin-spam-be-gone": "^0.4.0",