chore: release 1.2.0 (#527)

* updated CHANGELOG.md [ci skip]

* updated package.json [ci skip]

* updated samples/package.json [ci skip]

Author: release-please[bot]

dialogflow/package.json

@@ -15,7 +15,7 @@
     "test": "mocha system-test --timeout=600000"
   },
   "dependencies": {
-    "dialogflow": "^1.1.2",
+    "dialogflow": "^1.2.0",
     "pb-util": "^0.1.0",
     "uuid": "^3.3.2",
     "yargs": "^15.0.0"