kill transition group

package.json

@@ -21,8 +21,7 @@
     "classnames": "^2.2.5",
     "prop-types": "^15.5.8",
     "react": "^15.5.4",
-    "react-dom": "^15.5.4",
-    "react-transition-group": "^2.0.2"
+    "react-dom": "^15.5.4"
   },
   "devDependencies": {
     "@storybook/addon-options": "^3.1.6",