chore(package): update jest to version 22.0.4

Closes #19

Author: greenkeeper[bot]

package.json

@@ -47,7 +47,7 @@
     "flow-bin": "^0.58.0",
     "flow-coverage-report": "^0.4.0",
     "github-changes": "^1.1.0",
-    "jest": "^21.2.1",
+    "jest": "^22.0.4",
     "localtunnel": "^1.8.3",
     "nodemon": "^1.12.1",
     "now": "^8.3.11",