ci(deps): bump actions/setup-node from 5 to 6 (#559)

Bumps [actions/setup-node](https://github.com/actions/setup-node) from 5 to 6.
- [Release notes](https://github.com/actions/setup-node/releases)
- [Commits](actions/setup-node@v5...v6)

---
updated-dependencies:
- dependency-name: actions/setup-node
  dependency-version: '6'
  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>

Author: dependabot[bot]

.github/workflows/build_docs.yml

@@ -40,7 +40,7 @@ jobs:
 
       # Install katex for math support
       - name: Install NPM
-        uses: actions/setup-node@v5
+        uses: actions/setup-node@v6
         with:
           node-version: 16
       - name: Install KaTeX