chore: release 2.8.1 (#128)

🤖 I have created a release \*beep\* \*boop\*
---
### [2.8.1](https://www.github.com/googleapis/nodejs-dialogflow-cx/compare/v2.8.0...v2.8.1) (2021-06-10)


### Bug Fixes

* GoogleAdsError missing using generator version after 1.3.0 ([#122](https://www.github.com/googleapis/nodejs-dialogflow-cx/issues/122)) ([af8ca45](https://www.github.com/googleapis/nodejs-dialogflow-cx/commit/af8ca45c8d70264899bb458f68d6b5c0060229fa))
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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).

dialogflow-cx/package.json

@@ -13,7 +13,7 @@
     "test": "c8 mocha --timeout 600000 test/*.js"
   },
   "dependencies": {
-    "@google-cloud/dialogflow-cx": "^2.8.0",
+    "@google-cloud/dialogflow-cx": "^2.8.1",
     "uuid": "^8.3.1"
   },
   "devDependencies": {