Add concurrency

Author: ddelange

.github/workflows/ci.yml

@@ -1,5 +1,8 @@
 name: ci
 on: [push, pull_request]
+concurrency:  # https://stackoverflow.com/questions/66335225#comment133398800_72408109
+  group: ${{ github.workflow }}-${{ github.ref || github.run_id }}
+  cancel-in-progress: ${{ github.event_name == 'pull_request' }}
 jobs:
   ci:
     strategy:

.github/workflows/wheels.yml

@@ -8,8 +8,11 @@ on:
     types: [released, prereleased]
   workflow_dispatch:  # allows running workflow manually from the Actions tab
 
-jobs:
+concurrency:  # https://stackoverflow.com/questions/66335225#comment133398800_72408109
+  group: ${{ github.workflow }}-${{ github.ref || github.run_id }}
+  cancel-in-progress: ${{ github.event_name == 'pull_request' }}
 
+jobs:
   build-sdist:
     runs-on: ubuntu-latest