chore(python): Use latest python runtime in prerelease_deps session (#…

…287)

Source-Link: googleapis/synthtool@14d8b28
Post-Processor: gcr.io/cloud-devrel-public-resources/owlbot-python:latest@sha256:5651442a6336971a2fb2df40fb56b3337df67cafa14c0809cc89cb34ccee1b8e

Co-authored-by: Owl Bot <gcf-owl-bot[bot]@users.noreply.github.com>

.github/.OwlBot.lock.yaml

@@ -13,5 +13,5 @@
 # limitations under the License.
 docker:
   image: gcr.io/cloud-devrel-public-resources/owlbot-python:latest
-  digest: sha256:d3de8a02819f65001effcbd3ea76ce97e9bcff035c7a89457f40f892c87c5b32
-# created: 2024-07-03T17:43:00.77142528Z
+  digest: sha256:5651442a6336971a2fb2df40fb56b3337df67cafa14c0809cc89cb34ccee1b8e
+# created: 2024-07-04T19:38:10.086106449Z

noxfile.py

@@ -367,7 +367,7 @@ def docfx(session):
     )
 
 
-@nox.session(python=SYSTEM_TEST_PYTHON_VERSIONS)
+@nox.session(python="3.12")
 @nox.parametrize(
     "protobuf_implementation",
     ["python", "upb", "cpp"],