ci: run one workflow per pull request with concurrency groups

.github/workflows/check.yml

@@ -4,13 +4,21 @@
 # As directed from:
 #   https://docs.github.com/en/actions/guides/building-and-testing-python#starting-with-the-python-workflow-template
 
+name: Check
+
 on:
   workflow_dispatch:
   pull_request:
   push:
     branches:
       - main
 
+# One run per pull request; a new event supersedes the one in flight.
+# Pushes to main and manual runs group by ref and always run to completion.
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
+  cancel-in-progress: ${{ github.event_name == 'pull_request' }}
+
 permissions: {}
 
 jobs:

.github/workflows/features.yml

@@ -6,6 +6,12 @@ on:
     branches:
       - main
 
+# One run per pull request; a new event supersedes the one in flight.
+# Pushes to main and manual runs group by ref and always run to completion.
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
+  cancel-in-progress: ${{ github.event_name == 'pull_request' }}
+
 permissions: {}
 
 jobs:

.github/workflows/lint.yml

@@ -6,6 +6,12 @@ on:
     branches:
       - main
 
+# One run per pull request; a new event supersedes the one in flight.
+# Pushes to main and manual runs group by ref and always run to completion.
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
+  cancel-in-progress: ${{ github.event_name == 'pull_request' }}
+
 permissions: {}
 
 jobs: