Build: Prevent redundant branch wheel builds for pull requests.

Author: scoder

.github/workflows/wheels.yml

@@ -32,6 +32,10 @@ on:
       - build*
   workflow_dispatch:
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.sha }}
+  cancel-in-progress: true
+
 permissions: {}
 
 env: