chore(package): update react-router to version 4.4.0

Closes #107

Author: greenkeeper[bot]

package.json

@@ -79,7 +79,7 @@
     "react": "^16.7.0",
     "react-dom": "^16.7.0",
     "react-redux": "^5.0.6",
-    "react-router": "^3.0.3",
+    "react-router": "^4.4.0",
     "react-test-renderer": "^16.7.0",
     "redux": "^3.7.2",
     "redux-mock-store": "^1.3.0",