chore: release 2.4.0 (#65)

🤖 I have created a release \*beep\* \*boop\*
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## [2.4.0](https://www.github.com/googleapis/nodejs-dialogflow-cx/compare/v2.3.0...v2.4.0) (2021-03-15)


### Features

* added fallback option when restoring an agent docs: clarified experiment length ([f90bb9c](https://www.github.com/googleapis/nodejs-dialogflow-cx/commit/f90bb9cd369659160a16fcfc67bc08c248bd1552))
* added fallback option when restoring an agent docs: clarified experiment length ([f90bb9c](https://www.github.com/googleapis/nodejs-dialogflow-cx/commit/f90bb9cd369659160a16fcfc67bc08c248bd1552))
* allow to disable webhook invocation per request ([f90bb9c](https://www.github.com/googleapis/nodejs-dialogflow-cx/commit/f90bb9cd369659160a16fcfc67bc08c248bd1552))
* allow to disable webhook invocation per request ([3b1b674](https://www.github.com/googleapis/nodejs-dialogflow-cx/commit/3b1b674bbddbcb26fa607f9dc16db6c43752c371))
* supports SentimentAnalysisResult in webhook request, add http rules for long running operations docs: minor ([3b1b674](https://www.github.com/googleapis/nodejs-dialogflow-cx/commit/3b1b674bbddbcb26fa607f9dc16db6c43752c371))


### Bug Fixes

* RunTestCase http template. PHP REST client lib can be generated. feat: Support transition route group coverage for Test Cases. feat: Support SentimentAnalysisResult input in the WebhookRequest. ([3b1b674](https://www.github.com/googleapis/nodejs-dialogflow-cx/commit/3b1b674bbddbcb26fa607f9dc16db6c43752c371))
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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]

dialogflow-cx/package.json

@@ -13,7 +13,7 @@
     "test": "c8 mocha --timeout 600000 test/*.js"
   },
   "dependencies": {
-    "@google-cloud/dialogflow-cx": "^2.3.0",
+    "@google-cloud/dialogflow-cx": "^2.4.0",
     "uuid": "^8.3.1"
   },
   "devDependencies": {