feat(ci): kill duplicate CI jobs on PRs (#26945)

.github/workflows/superset-python-misc.yml

@@ -12,6 +12,11 @@ on:
     paths:
       - "superset/**"
 
+# cancel previous workflow jobs for PRs
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.run_id }}
+  cancel-in-progress: true
+
 jobs:
   python-lint:
     runs-on: ubuntu-20.04