Use always() instead of !cancelled()

Normally you want to avoid `always()` in favor of `!cancelled()`, but in this case we want to use `always()` because using `!cancelled()` would lead to the `ci` job being skipped, which would report as a success for the status check.

.github/workflows/pr.yml

@@ -154,7 +154,7 @@ jobs:
   ci:
     runs-on: ubuntu-latest
     name: CI
-    if: ${{ !cancelled() }}
+    if: ${{ always() }} # need to use always() instead of !cancelled() because skipped jobs count as success 
     needs:
       - clang-cuda
       - cub