ci: update trigger

Author: KD-7

.github/workflows/clean_deployments.yml

@@ -8,11 +8,11 @@ on:
 
   # To share the secrets between jobs for our Python Publish Action, we need to use
   # an environment which creates multiple deployments.
-  # This action cleans up the GitHub PR when the deployments are
-  # no longer needed.
-  # Due to API limitations, we cant call this action from the Python Publish Action,
-  # so we need to call this on each PR.
-  pull_request:
+  # This action cleans up the GitHub PR when the deployments are no longer needed.
+  workflow_run:
+    workflows: ["Upload Python Package"]
+    types:
+      - completed
 
 jobs:
   cleanup: