Bump actions/download-artifact from 2 to 4.1.7 in /.github/workflows

Bumps [actions/download-artifact](https://github.com/actions/download-artifact) from 2 to 4.1.7.
- [Release notes](https://github.com/actions/download-artifact/releases)
- [Commits](https://github.com/actions/download-artifact/compare/v2...v4.1.7)

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

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/pages.yaml

@@ -90,12 +90,12 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - name: Fetch artifacts (first root then others so the ordering is correct)
-      uses: actions/download-artifact@v2
+      uses: actions/download-artifact@v4.1.7
       with:
         name: main-root
         path: ${{ github.workspace }}/docs/book
     - name: Fetch artifacts (first root then others so the ordering is correct)
-      uses: actions/download-artifact@v2
+      uses: actions/download-artifact@v4.1.7
       with:
         path: ${{ github.workspace }}/docs/pages
     - name: Install pages