fix(ci): use commit SHA for concurrency group

PR number vs ref gave different keys for push and pull_request events
on the same commit. Using SHA ensures both triggers for the same commit
share a group, so one gets cancelled.

Author: wazolab

.github/workflows/ci.yml

@@ -7,7 +7,7 @@ on:
     branches: [develop, main]
 
 concurrency:
-  group: ci-${{ github.event.pull_request.number || github.ref }}
+  group: ci-${{ github.sha }}
   cancel-in-progress: true
 
 jobs: