Configure concurrency for Danger CI workflow (#4646)

Added concurrency settings to Danger workflow.

.github/workflows/danger.yml

@@ -9,6 +9,11 @@ jobs:
     name: Danger
     runs-on: macos-15
 
+    concurrency:
+      # Only allow a single run of this workflow on each branch, automatically cancelling older runs.
+      group: ${{ format('danger-ci-{0}', github.ref) }}
+      cancel-in-progress: true
+
     steps:
       - name: Checkout
         uses: actions/checkout@v5
@@ -21,4 +26,4 @@ jobs:
         run: 
           danger-swift ci
         env: 
-          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}