Adjust CI job for concurency

This change prevents redundant Actions running on a PR.

Given a situation where a PR has been created and gets updates pushed.
Each update will trigger a new CI workflow to run, however only the most recent one is actually valid for the current state.
As such this change will prevent the redundant jobs from running, cancelling them without error, and will allow the correct workflow to run sooner.

.github/workflows/ci.yml

@@ -3,6 +3,10 @@ name: CI
 on:
   pull_request:
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
 permissions:
   contents: read