chore: update python version in release.sh (#3744)

* chore: update python version in release.sh

* update release.sh comment

Author: diegomarquezp

kokoro/ubuntu/release.sh

@@ -13,9 +13,9 @@ gsutil -q cp "gs://ct4e-m2-repositories-for-kokoro/m2-cache.tar" - \
 export CLOUDSDK_CORE_DISABLE_USAGE_REPORTING=true
 gcloud components update --quiet
 
-# More recent Cloud SDK requires Python 3.5 (b/194714889)
+# More recent Cloud SDK requires Python 3.8 - 3.12
 if [ -z "$CLOUDSDK_PYTHON" ]; then
-    export CLOUDSDK_PYTHON=python3.5
+    export CLOUDSDK_PYTHON=python3.12
 fi
 gcloud components install app-engine-java --quiet