Merge pull request #4488 from mozilla/greenkeeper/raven-js-3.23.1

Update raven-js to the latest version 🚀

package.json

@@ -183,7 +183,7 @@
     "prop-types": "15.6.1",
     "raf": "3.4.0",
     "raven": "2.3.0",
-    "raven-js": "3.23.0",
+    "raven-js": "3.23.1",
     "rc-tooltip": "3.7.0",
     "react": "16.2.0",
     "react-autosuggest": "9.3.4",