actions: upgrade action-download-artifact

Author: fprochazka

.github/workflows/publish-test-results.yml

@@ -13,7 +13,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Download Test Report
-        uses: dawidd6/action-download-artifact@v2
+        uses: dawidd6/action-download-artifact@6
         with:
           name: junit-test-results
           workflow: ${{ github.event.workflow.id }}