chore(deps): update dependency urllib3 to v2.6.3 [security] (#8848)

Author: renovate-bot

.kokoro/docs/docker/requirements.txt

@@ -140,7 +140,7 @@ rsa==4.9.1 \
     --hash=sha256:68635866661c6836b8d39430f97a996acbd61bfa49406748ea243539fe239762 \
     --hash=sha256:e7bdbfdb5497da4c07dfd35530e1a902659db6ff241e39d9953cad06ebd0ae75
     # via google-auth
-urllib3==2.6.0 \
-    --hash=sha256:c90f7a39f716c572c4e3e58509581ebd83f9b59cced005b7db7ad2d22b0db99f \
-    --hash=sha256:cb9bcef5a4b345d5da5d145dc3e30834f58e8018828cbc724d30b4cb7d4d49f1
+urllib3==2.6.3 \
+    --hash=sha256:1b62b6884944a57dbe321509ab94fd4d3b307075e0c2eae991ac71ee15ad38ed \
+    --hash=sha256:bf272323e553dfb2e87d9bfd225ca7b0f467b919d7bbd355436d3fd37cb0acd4
     # via requests