maint: bump actions/upload-artifact from 4.5.0 to 4.6.0 (#547)

Bumps [actions/upload-artifact](https://github.com/actions/upload-artifact) from 4.5.0 to 4.6.0.
- [Release notes](https://github.com/actions/upload-artifact/releases)
- [Commits](actions/upload-artifact@v4.5.0...v4.6.0)

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

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/nightly-build.yml

@@ -45,14 +45,14 @@ jobs:
           make -C doc pdf
 
       - name: Upload HTML documentation
-        uses: actions/upload-artifact@v4.5.0
+        uses: actions/upload-artifact@v4.6.0
         with:
           name: HTML-Documentation
           path: doc/_build/html
           retention-days: 7
 
       - name: Upload PDF Documentation
-        uses: actions/upload-artifact@v4.5.0
+        uses: actions/upload-artifact@v4.6.0
         with:
           name: PDF-Documentation
           path: doc/_build/latex/pyansys*.pdf