Allow branches to run concurrently since they don't deploy

Author: marcphilipp

.github/workflows/deploy-docs.yml

@@ -8,7 +8,7 @@ on:
   workflow_dispatch:
 
 concurrency:
-  group: ${{ github.workflow }}
+  group: ${{ github.workflow }}-${{ github.ref }}
   cancel-in-progress: true
 
 permissions: {}