Bump actions/upload-artifact from 2 to 3 (#223)

Bumps [actions/upload-artifact](https://github.com/actions/upload-artifact) from 2 to 3.
- [Release notes](https://github.com/actions/upload-artifact/releases)
- [Commits](actions/upload-artifact@v2...v3)

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

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

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

.github/workflows/release.yaml

@@ -31,7 +31,7 @@ jobs:
           mkdocs build --clean
 
       - name: Upload pdf
-        uses: actions/upload-artifact@v2
+        uses: actions/upload-artifact@v3
         with:
           name: artifact
           path: site/pdf/document.pdf