Only run CI for branch tips

.github/workflows/build.yml

@@ -2,6 +2,10 @@ name: Build
 on:
   push:
 
+concurrency:
+  group: ${{ github.ref }}
+  cancel-in-progress: true
+
 jobs:
   checks:
     runs-on: ubuntu-latest

.github/workflows/deploy.yaml

@@ -1,5 +1,9 @@
 name: Deploy DNF repo
 
+concurrency:
+  group: deploy
+  cancel-in-progress: true
+
 on:
   release:
     types: [released]