chore(package): update jest to version 21.0.0 (mattphillips#18)

Author: greenkeeper[bot]

package.json

@@ -26,7 +26,7 @@
  "babel-preset-es2015": "^6.18.0",
  "babel-preset-stage-0": "^6.16.0",
  "coveralls": "^2.11.15",
- "jest": "^20.0.1",
+ "jest": "^21.0.0",
  "jest-each": "0.2.0"
  },
  "babel": {