ci: bench fix concurrency for workflow trigger dispatch with sha1 (ggml-org#6478)

Author: phymbert

.github/workflows/bench.yml

@@ -32,7 +32,7 @@ on:
     -  cron: '04 2 * * *'
 
 concurrency:
-  group: ${{ github.workflow }}-${{ github.ref }}
+  group: ${{ github.workflow }}-${{ github.ref }}-${{ github.event.inputs.sha }}
   cancel-in-progress: true
 
 jobs: