Bump react-router from 3.2.0 to 5.1.2

Bumps [react-router](https://github.com/ReactTraining/react-router) from 3.2.0 to 5.1.2.
- [Release notes](https://github.com/ReactTraining/react-router/releases)
- [Changelog](https://github.com/ReactTraining/react-router/blob/master/CHANGELOG.md)
- [Commits](remix-run/react-router@v3.2.0...v5.1.2)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

package.json

@@ -205,7 +205,7 @@
     "react-markdown": "4.2.2",
     "react-progress-bar.js": "0.2.3",
     "react-redux": "^5.0.6",
-    "react-router": "3.2.0",
+    "react-router": "5.1.2",
     "react-router-redux": "4.0.8",
     "react-transition-group": "2.9.0",
     "redux": "3.7.2",