Upgrade Jest testing libraries.

package.json

@@ -66,7 +66,7 @@
     "babel": "^6.5.2",
     "babel-cli": "^6.18.0",
     "babel-core": "^6.23.1",
-    "babel-jest": "^20.0.3",
+    "babel-jest": "^21.2.0",
     "babel-loader": "^7.0.0",
     "babel-plugin-lodash": "^3.2.0",
     "babel-preset-es2015": "^6.22.0",
@@ -86,8 +86,8 @@
     "file-loader": "^1.1.4",
     "identity-obj-proxy": "^3.0.0",
     "imports-loader": "^0.7.1",
-    "jest": "^20.0.4",
-    "jest-cli": "^20.0.4",
+    "jest": "^21.2.1",
+    "jest-cli": "^21.2.1",
     "lint-staged": "^3.3.1",
     "npm-check": "^5.2.3",
     "postcss-cssnext": "^2.7.0",