chore(deps): update dependency google-cloud-bigquery to v2.28.0 (#229)

Author: renovate-bot

bigquery-datatransfer/snippets/requirements-test.txt

@@ -1,4 +1,4 @@
-google-cloud-bigquery==2.27.1
+google-cloud-bigquery==2.28.0
 google-cloud-pubsub==2.8.0
 pytest==6.2.5
 mock==4.0.3