chore: release 2.4.0 (#563)

🤖 I have created a release \*beep\* \*boop\*
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## [2.4.0](https://www.github.com/googleapis/nodejs-tasks/compare/v2.3.6...v2.4.0) (2021-09-07)


### Features

* turns on self-signed JWT feature flag ([#561](https://www.github.com/googleapis/nodejs-tasks/issues/561)) ([9fde4fe](https://www.github.com/googleapis/nodejs-tasks/commit/9fde4fe9a7274493ce0b4bb1a2d25bd85a3e9af2))
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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]

cloud-tasks/package.json

@@ -15,7 +15,7 @@
     "start": "node server.js"
   },
   "dependencies": {
-    "@google-cloud/tasks": "^2.3.6",
+    "@google-cloud/tasks": "^2.4.0",
     "body-parser": "^1.18.3",
     "express": "^4.16.3"
   },