ci: add concurrency option to skip in progress

Instead of running outdated CI jobs, skip them automatically.

Signed-off-by: Paul Spooren <mail@aparcar.org>

.github/workflows/nix.yaml

@@ -6,6 +6,11 @@ on:
   push:
     branches:
       - main
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
 jobs:
   i686-linux---default:
     name: Build i686-linux.default

.github/workflows/qc.yaml

@@ -4,6 +4,10 @@ on:
   push:
     branches: [main]
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
 permissions:
   checks: write
   contents: read

.github/workflows/regressions.yml

@@ -4,6 +4,10 @@ on:
   push:
     branches: [main]
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
 permissions:
   checks: write
   contents: read