ci: allow manual dispatch for coverage job

Signed-off-by: Mason Hu <[email protected]>

.github/workflows/coverage.yaml

@@ -1,5 +1,6 @@
 name: Test coverage
 on:
+  workflow_dispatch:
   push:
     branches:
       - main
@@ -64,7 +65,7 @@ jobs:
 
       - uses: actions/setup-node@v4
         with:
-          node-version: 18
+          node-version: 20
 
       - name: Install Playwright Browser
         run: npx playwright install --with-deps chromium
@@ -79,9 +80,17 @@ jobs:
           DOTRUN_CONTAINER_ID=$(docker ps | awk '{print $1}' | tail -n1)
           docker stop $DOTRUN_CONTAINER_ID
 
+      - name: Show contents in workspace
+        run: |
+          ls ${{ github.workspace }}
+          find .
+
+      - name: Show contents in coverage directory
+        run: ls coverage/playwright-report
+
       - name: Upload coverage report
         if: always()
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@v3
         with:
           name: lxd-coverage
           path: coverage/playwright-report