Automatically disable stale pipelines

.github/workflows/ci.yml

@@ -2,6 +2,10 @@ name: CI
 
 on: [push, pull_request]
 
+concurrency:
+  group: environment-${{github.ref}}
+  cancel-in-progress: true
+
 jobs:
   build:
     name: ${{ matrix.platform.name }} ${{ matrix.type.name }}