Remove workflow tweak for triggering AIO testing upon push.

Author: maxstack

.github/workflows/stackhpc-pull-request.yml

@@ -7,8 +7,6 @@ concurrency:
 name: Pull request
 'on':
   pull_request:
-  # FIXME: Remove
-  push:
 jobs:
   # Detect which files have changed and use this to run jobs conditionally.
   # Note that we can't use the workflow-level paths attribute since this