Remove unused dev dependency

Author: hubgit

react-prosemirror/package.json

@@ -21,7 +21,6 @@
     "prosemirror-view": "^1.0.0"
   },
   "devDependencies": {
-    "@aeaton/react-prosemirror-config-default": "^0.8.8",
     "babel-core": "^6.26.0",
     "babel-loader": "^7.1.2",
     "babel-preset-env": "^1.6.1",