Update jest requirement to ^23.4.2

Updates the requirements on [jest](https://github.com/facebook/jest) to permit the latest version.
- [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/v23.4.2)

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

package.json

@@ -34,7 +34,7 @@
     "@types/node": "^10.5.2",
     "@types/p-queue": "^2.3.1",
     "coveralls": "^3.0.2",
-    "jest": "^22.4.3",
+    "jest": "^23.4.2",
     "nodemon": "^1.17.2",
     "smee-client": "^1.0.2",
     "standard": "^11.0.1",