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/tmate_debug/action.yml

@@ -1,8 +1,8 @@
-name: "Tmate debugging tests"
-description: "Setup tmate session if the test fails"
+name: "Tmate debugging for tests"
+description: "Set up an ssh session for interactive debugging of failing tests"
 inputs:
   use-tmate:
-    description: "boolean for enabling TMATE"
+    description: "boolean for enabling tmate"
     required: true
   debug-ci:
     description: "boolean for debug-ci label in PR"
@@ -10,18 +10,19 @@ inputs:
 runs:
   using: "composite"
   steps:
-    - name: consider debugging
+    - name: consider tmate debugging
       shell: bash --noprofile --norc -eo pipefail -x {0}
       if: runner.debug || inputs.debug-ci == 'true'
       run: |
         # Enable tmate only in the Rook fork, where the USE_TMATE secret is set in the repo, or if the action is re-run
         if [ "$GITHUB_REPOSITORY_OWNER" = "rook" ] || [ -n "${{ inputs.use-tmate }}" ] || [ "$GITHUB_RUN_ATTEMPT" -gt 1 ]; then
-          echo USE_TMATE=1 >> $GITHUB_ENV
+          echo ENABLE_TMATE=1 >> $GITHUB_ENV
         fi
 
-    - name: set up tmate session for debugging
-      if: env.USE_TMATE
+    - name: set up tmate session
+      if: env.ENABLE_TMATE
       uses: mxschmitt/action-tmate@v3
       with:
+        ## whether to limit ssh access and adds the ssh public key for the user who triggered the workflow:
         limit-access-to-actor: false
         detached: true