ci(deploy): cancel in-progress Pages deploys

Only the latest build matters for a static site; cancelling superseded
deploys collapses rapid bursts (e.g. dep-merge + release-bump pushes) to a
single Pages API call, avoiding the transient 'Deployment failed, try again
later' race.

Author: Endika

.github/workflows/deploy.yml

@@ -12,7 +12,7 @@ permissions:
 
 concurrency:
   group: pages
-  cancel-in-progress: false
+  cancel-in-progress: true
 
 jobs:
   build-and-deploy:
@@ -33,4 +33,4 @@ jobs:
         with:
           path: dist
       - id: deploy
-        uses: actions/deploy-pages@v5
+        uses: actions/deploy-pages@v5