Enable retain runs. (Azure#18200)

Author: mitchdenny

eng/pipelines/templates/stages/archetype-python-release.yml

@@ -31,7 +31,7 @@ stages:
                 deploy:
                   steps:
                     - checkout: self
-
+                    - template: /eng/common/pipelines/templates/steps/retain-run.yml
                     - template: /eng/common/pipelines/templates/steps/set-test-pipeline-version.yml
                       parameters:
                         PackageName: "azure-template"