Bump actions/download-artifact from 4.1.7 to 4.1.8

Bumps [actions/download-artifact](https://github.com/actions/download-artifact) from 4.1.7 to 4.1.8.
- [Release notes](https://github.com/actions/download-artifact/releases)
- [Commits](actions/download-artifact@v4.1.7...v4.1.8)

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

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

.github/workflows/docs.yml

@@ -79,13 +79,13 @@ jobs:
       - uses: actions/[email protected]
 
       - name: download current docs
-        uses: actions/[email protected].7
+        uses: actions/[email protected].8
         with:
           name: current_documentation
           path: new_documentation
 
       - name: download new docs
-        uses: actions/[email protected].7
+        uses: actions/[email protected].8
         with:
           name: generated_documentation
           path: generated_documentation