chore(package): update react-router to version 4.2.0

Closes #107

Author: greenkeeper[bot]

package.json

@@ -77,7 +77,7 @@
     "react": "^15.6.1",
     "react-dom": "^15.6.1",
     "react-redux": "^5.0.5",
-    "react-router": "^3.0.3",
+    "react-router": "^4.2.0",
     "react-test-renderer": "^15.6.1",
     "redux": "^3.7.1",
     "redux-mock-store": "^1.2.2",