chore: librarian update image pull request: 20251212T194254Z (#203)

feat: update image to
us-central1-docker.pkg.dev/cloud-sdk-librarian-prod/images-prod/python-librarian-generator@sha256:d7caef319a25d618e20ba798b103434700bfd80015f525802d87621ca2528c90

This PR was created using the following command
```
partheniou@partheniou-vm-3:~/git/google-auth-library-python-httplib2$ librarian update-image -push
...
time=2025-12-12T19:42:56.257Z level=INFO msg="creating PR" branch=librarian-20251212T194254Z base=main title="chore: librarian update image pull request: 20251212T194254Z"
time=2025-12-12T19:42:57.264Z level=INFO msg="pr created" url=#203
time=2025-12-12T19:42:57.264Z level=INFO msg="labels added to issue" number=203 labels=[]
```

Author: parthea

.librarian/state.yaml

@@ -1,7 +1,8 @@
-image: us-central1-docker.pkg.dev/cloud-sdk-librarian-prod/images-prod/python-librarian-generator@sha256:c8612d3fffb3f6a32353b2d1abd16b61e87811866f7ec9d65b59b02eb452a620
+image: us-central1-docker.pkg.dev/cloud-sdk-librarian-prod/images-prod/python-librarian-generator@sha256:d7caef319a25d618e20ba798b103434700bfd80015f525802d87621ca2528c90
 libraries:
   - id: google-auth-httplib2
     version: 0.2.1
+    last_generated_commit: ""
     apis: []
     source_roots:
       - .