[babel] Move babel-core to the devDependencies

Author: oliviertassinari

package.json

@@ -24,10 +24,9 @@
   "bugs": {
     "url": "https://github.com/oliviertassinari/babel-plugin-react-remove-properties/issues"
   },
-  "dependencies": {
-    "babel-core": "^6.2.1"
-  },
+  "dependencies": {},
   "devDependencies": {
+    "babel-core": "^6.2.1",
     "babel-cli": "^6.2.0",
     "babel-preset-es2015": "^6.6.0",
     "babel-preset-react": "^6.1.18",