chore(python): fix docs publish build

Source-Link: googleapis/synthtool@bd9ede2
Post-Processor: gcr.io/cloud-devrel-public-resources/owlbot-python:latest@sha256:04c35dc5f49f0f503a306397d6d043685f8d2bb822ab515818c4208d7fb2db3a

Author: gcf-owl-bot[bot]

.github/.OwlBot.lock.yaml

@@ -1,4 +1,4 @@
-# Copyright 2024 Google LLC
+# Copyright 2025 Google LLC
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -13,5 +13,5 @@
 # limitations under the License.
 docker:
   image: gcr.io/cloud-devrel-public-resources/owlbot-python:latest
-  digest: sha256:5efdf8d38e5a22c1ec9e5541cbdfde56399bdffcb6f531183f84ac66052a8024
-# created: 2024-10-25
+  digest: sha256:04c35dc5f49f0f503a306397d6d043685f8d2bb822ab515818c4208d7fb2db3a
+# created: 2025-01-16T15:24:11.364245182Z

.kokoro/docker/docs/requirements.in

@@ -1 +1,2 @@
 nox
+gcp-docuploader