build(deps): bump dawidd6/action-download-artifact in /.github/workflows

Bumps [dawidd6/action-download-artifact](https://github.com/dawidd6/action-download-artifact) from 2 to 6.
- [Release notes](https://github.com/dawidd6/action-download-artifact/releases)
- [Commits](dawidd6/action-download-artifact@v2...v6)

---
updated-dependencies:
- dependency-name: dawidd6/action-download-artifact
  dependency-type: direct:production
...

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

.github/workflows/pages.yml

@@ -28,7 +28,7 @@ jobs:
       - name: Set up directory tree
         run: mkdir -p public_html/doc/
       - name: Download doxygen from Linux build
-        uses: dawidd6/action-download-artifact@v2
+        uses: dawidd6/action-download-artifact@v6
         with:
           workflow: linux.yml
           workflow_conclusion: success