Bump actions/setup-node from 5 to 6 in the actions group

Bumps the actions group with 1 update: [actions/setup-node](https://github.com/actions/setup-node).


Updates `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
  dependency-group: actions
...

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

Author: dependabot[bot]

.github/workflows/deploy.yml

@@ -30,7 +30,7 @@ jobs:
       - uses: actions/checkout@v5
       - name: Setup Pages
         uses: actions/configure-pages@v5
-      - uses: actions/setup-node@v5
+      - uses: actions/setup-node@v6
         with:
           node-version: 18.x
       - name: Install MyST Markdown