migrate librarian

Author: parthea

.librarian/state.yaml

@@ -4304,3 +4304,11 @@ libraries:
       - README.rst
       - docs/summary_overview.md
     tag_format: '{id}-v{version}'
+  - id: google-api-core
+    version: 2.28.1
+    apis: []
+    source_roots:
+      - .
+    preserve_regex: []
+    remove_regex: []
+    tag_format: v{version}