ci: cancel previous actions

Author: xrdavies

.github/workflows/main.yml

@@ -6,11 +6,13 @@ on:
       - main
   pull_request:
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
 jobs:
   deploy:
     runs-on: ubuntu-20.04
-    concurrency:
-      group: ${{ github.workflow }}-${{ github.ref }}
     steps:
       - uses: actions/checkout@v2