Bump actions/download-artifact from 5 to 6

Bumps [actions/download-artifact](https://github.com/actions/download-artifact) from 5 to 6.
- [Release notes](https://github.com/actions/download-artifact/releases)
- [Commits](actions/download-artifact@v5...v6)

---
updated-dependencies:
- dependency-name: actions/download-artifact
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

.github/workflows/pr-label-on-approved.yml

@@ -15,7 +15,7 @@ jobs:
 
     steps:
       - name: Download PR number artifact from upstream run
-        uses: actions/download-artifact@v5
+        uses: actions/download-artifact@v6
         with:
           name: pr-number-${{ github.event.workflow_run.id }}   # same unique name
           path: .

.github/workflows/unit-tests.yml

@@ -153,7 +153,7 @@ jobs:
     steps:
 
       - name: Download All Artifacts
-        uses: actions/download-artifact@v5
+        uses: actions/download-artifact@v6
         with:
           path: test
           pattern: test-*