ci: add upterm debugging as an alternative to tmate

This enables interactive debugging of ci checks
with the upterm tool as an alternative to the tmate tool which does not
work entirely anymore.
see https://github.com/rook/rook/issues/16131

addition to tmate, upterm debugging is now enabled via the debug-ci label on
PRs

Signed-off-by: Michael Adam <obnox@samba.org>

.github/workflows/multus.yaml

@@ -51,7 +51,7 @@ jobs:
           config: tests/scripts/multus/kind-config.yaml
           cluster_name: kind
 
-      - name: consider debugging
+      - name: consider (pre-job) debugging
         uses: ./.github/workflows/tmate_debug
         with:
           use-tmate: ${{ secrets.USE_TMATE }}
@@ -111,3 +111,8 @@ jobs:
         # independent from other tests as long as nodes are tainted and labeled
         if: steps.taint.outcome == 'success' && !cancelled()
         run: ./tests/scripts/multus/test-240-stretch-cluster-only.sh
+
+      - name: consider (post-job) debugging
+        uses: ./.github/workflows/upterm_debug
+        with:
+          debug-ci: ${{ contains(github.event.pull_request.labels.*.name, 'debug-ci') }}