ci: stop previous deploy if a new one starts

.github/workflows/deploy.yml

@@ -5,6 +5,9 @@ on:
     push:
         branches:
             - master
+concurrency:
+    group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
+    cancel-in-progress: true
 jobs:
     deploy:
         if: ${{ github.repository_owner == 'developomp' }}