chore(deps): update dependency google-cloud-pubsub to v1.6.1 [(#4242)](GoogleCloudPlatform/python-docs-samples#4242)

Co-authored-by: gcf-merge-on-green[bot] <60162190+gcf-merge-on-green[bot]@users.noreply.github.com>

Author: renovate-bot

samples/snippets/requirements.txt

@@ -1,5 +1,5 @@
 google-cloud-dlp==1.0.0
 google-cloud-storage==1.29.0
-google-cloud-pubsub==1.6.0
+google-cloud-pubsub==1.6.1
 google-cloud-datastore==1.12.0
 google-cloud-bigquery==1.25.0