update librarian config to skip generation

Author: ohmayr

librarian.yaml

@@ -1687,6 +1687,8 @@ libraries:
     version: 2.39.0
     apis:
       - path: google/pubsub/v1
+    skip_generate: true
+    skip_release: true
     python:
       library_type: GAPIC_COMBO
       opt_args_by_api:
@@ -1921,6 +1923,8 @@ libraries:
       - path: google/spanner/v1
       - path: google/spanner/admin/instance/v1
       - path: google/spanner/admin/database/v1
+    skip_generate: true
+    skip_release: true
     keep:
       - docs/spanner_v1/batch.rst
       - docs/spanner_v1/client.rst