chore(package): update jest to version 21.0.1

Closes #122

Author: greenkeeper[bot]

package.json

@@ -43,7 +43,7 @@
     "eslint-config-airbnb-base": "^11.2.0",
     "eslint-plugin-import": "^2.7.0",
     "husky": "^0.14.3",
-    "jest": "^20.0.4",
+    "jest": "^21.0.1",
     "lint-staged": "^4.0.1",
     "lodash": "^4.15.0",
     "prettier": "^1.4.4",