chore: release 2.9.0 (#135)

🤖 I have created a release \*beep\* \*boop\*
---
## [2.9.0](https://www.github.com/googleapis/nodejs-dialogflow-cx/compare/v2.8.1...v2.9.0) (2021-06-14)


### Features

* added API for running continuous test ([#123](https://www.github.com/googleapis/nodejs-dialogflow-cx/issues/123)) ([248ae74](https://www.github.com/googleapis/nodejs-dialogflow-cx/commit/248ae742e786dd24f8a0e8161a1a30f684c3b7ff))
---


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

dialogflow-cx/package.json

@@ -13,7 +13,7 @@
     "test": "c8 mocha --timeout 600000 test/*.js"
   },
   "dependencies": {
-    "@google-cloud/dialogflow-cx": "^2.8.1",
+    "@google-cloud/dialogflow-cx": "^2.9.0",
     "uuid": "^8.3.1"
   },
   "devDependencies": {