librarian bigframes version to 2.29.0

Author: GarrettWu

.librarian/state.yaml

@@ -1,7 +1,7 @@
 image: us-central1-docker.pkg.dev/cloud-sdk-librarian-prod/images-prod/python-librarian-generator@sha256:c8612d3fffb3f6a32353b2d1abd16b61e87811866f7ec9d65b59b02eb452a620
 libraries:
   - id: bigframes
-    version: 2.29.1
+    version: 2.29.0
     apis: []
     source_roots:
       - .