Bump jest from 22.4.2 to 22.4.3 in /helpers/npm

Bumps [jest](https://github.com/facebook/jest) from 22.4.2 to 22.4.3.
- [Release notes](https://github.com/facebook/jest/releases)
- [Changelog](https://github.com/facebook/jest/blob/master/CHANGELOG.md)
- [Commits](https://github.com/facebook/jest/commits)

Signed-off-by: dependabot[bot] <support@dependabot.com>

helpers/npm/package.json

@@ -8,7 +8,7 @@
     "eslint": "^4.19.1",
     "eslint-plugin-prettier": "^2.6.0",
     "fs-extra": "^5.0.0",
-    "jest": "^22.4.2",
+    "jest": "^22.4.3",
     "nock": "^9.2.3",
     "prettier": "^1.11.1"
   }