chore(deps): update dependency google-cloud-pubsub to v2.6.0 (#170)

Author: renovate-bot

dlp/snippets/requirements.txt

@@ -1,5 +1,5 @@
 google-cloud-dlp==3.1.1
 google-cloud-storage==1.39.0
-google-cloud-pubsub==2.5.0
+google-cloud-pubsub==2.6.0
 google-cloud-datastore==2.1.3
 google-cloud-bigquery==2.20.0