chore: release 2.2.4 (#386)

🤖 I have created a release \*beep\* \*boop\*
---
### [2.2.4](https://www.github.com/googleapis/nodejs-scheduler/compare/v2.2.3...v2.2.4) (2021-06-30)


### Bug Fixes

* **deps:** google-gax v2.17.0 with mTLS ([#384](https://www.github.com/googleapis/nodejs-scheduler/issues/384)) ([c36a09b](https://www.github.com/googleapis/nodejs-scheduler/commit/c36a09b5ef57c1fd1e9232d4c3eac54024ec5a15))
---


This PR was generated with [Release Please](https://github.com/googleapis/release-please). See [documentation](https://github.com/googleapis/release-please#release-please).

Author: release-please[bot]

scheduler/package.json

@@ -14,7 +14,7 @@
     "test": "mocha --timeout 10000 --exit"
   },
   "dependencies": {
-    "@google-cloud/scheduler": "^2.2.3",
+    "@google-cloud/scheduler": "^2.2.4",
     "body-parser": "^1.18.3",
     "express": "^4.16.4"
   },