ci: GitHub Actions cancels old jobs if a new one is started.

Author: henryborchers

.github/workflows/tox_matrix.yml

@@ -8,6 +8,12 @@ on:
         default: false
         type: boolean
 
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+
 name: Multi-platform Compatibility Test (Tox)
 jobs:
   build:

.github/workflows/wheels.yml

@@ -2,6 +2,10 @@ name: Build
 
 on: [push, pull_request]
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
 jobs:
   build_wheels:
     name: Build wheels on ${{ matrix.os }}