🦉 Updates from OwlBot post-processor

See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md

Author: gcf-owl-bot[bot]

docs/conf.py

@@ -109,6 +109,7 @@
 # List of patterns, relative to source directory, that match files and
 # directories to ignore when looking for source files.
 exclude_patterns = [
+    "google/cloud/bigquery_v2/**",  # Legacy proto-based types.
     "google/cloud/bigquery_v2/**",  # Legacy proto-based types.
     "google/cloud/bigquery_v2/**",  # Legacy proto-based types.
     "_build",