chore: release dialogflow 1.2.0 (#5016)

diff --git a/dialogflow/CHANGES.md b/dialogflow/CHANGES.md
index 8bc85d0..e0de1af 100644
--- a/dialogflow/CHANGES.md
+++ b/dialogflow/CHANGES.md
@@ -1,5 +1,13 @@
 # Changes
 
+## [1.2.0](https://www.github.com/googleapis/google-cloud-go/compare/dialogflow/v1.1.0...dialogflow/v1.2.0) (2021-11-02)
+
+
+### Features
+
+* **dialogflow/cx:** added API for changelogs docs: clarified semantic of the streaming APIs ([587bba5](https://www.github.com/googleapis/google-cloud-go/commit/587bba5ad792a92f252107aa38c6af50fb09fb58))
+* **dialogflow/cx:** added API for changelogs docs: clarified semantic of the streaming APIs ([587bba5](https://www.github.com/googleapis/google-cloud-go/commit/587bba5ad792a92f252107aa38c6af50fb09fb58))
+
 ## [1.1.0](https://www.github.com/googleapis/google-cloud-go/compare/dialogflow/v1.0.0...dialogflow/v1.1.0) (2021-10-18)