chore(librarian): onboard to librarian (#977)

Towards googleapis/librarian#2456

Author: parthea

.github/.OwlBot.lock.yaml

@@ -0,0 +1,10 @@
+image: us-central1-docker.pkg.dev/cloud-sdk-librarian-prod/images-prod/python-librarian-generator:latest
+libraries:
+  - id: pandas-gbq
+    version: 0.30.0
+    apis: []
+    source_roots:
+      - .
+    preserve_regex: []
+    remove_regex: []
+    tag_format: v{version}

.github/.OwlBot.yaml

@@ -1,5 +1,9 @@
 # Changelog
 
+[PyPI History][1]
+
+[1]: https://pypi.org/project/pandas-gbq/#history
+
 ## [0.30.0](https://github.com/googleapis/python-bigquery-pandas/compare/v0.29.2...v0.30.0) (2025-10-31)