Bump the actions group with 3 updates

Bumps the actions group with 3 updates: [actions/checkout](https://github.com/actions/checkout), [actions/setup-node](https://github.com/actions/setup-node) and [actions/upload-pages-artifact](https://github.com/actions/upload-pages-artifact).


Updates `actions/checkout` from 4 to 5
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v4...v5)

Updates `actions/setup-node` from 4 to 6
- [Release notes](https://github.com/actions/setup-node/releases)
- [Commits](actions/setup-node@v4...v6)

Updates `actions/upload-pages-artifact` from 3 to 4
- [Release notes](https://github.com/actions/upload-pages-artifact/releases)
- [Commits](actions/upload-pages-artifact@v3...v4)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: '5'
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: actions
- dependency-name: actions/setup-node
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: actions
- dependency-name: actions/upload-pages-artifact
  dependency-version: '4'
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: actions
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

.github/workflows/deploy-demo.js.yml

@@ -31,20 +31,20 @@ jobs:
 
       # --- checkout both branches ---
       - name: Checkout stable (demo)
-        uses: actions/checkout@v4
+        uses: actions/checkout@v5
         with:
           ref: demo
           path: demo_src
 
       - name: Checkout latest (main)
-        uses: actions/checkout@v4
+        uses: actions/checkout@v5
         with:
           ref: main
           path: main_src
 
       # --- node setup ---
       - name: Setup Node
-        uses: actions/setup-node@v4
+        uses: actions/setup-node@v6
         with:
           node-version: '20.18.1'
           cache: 'npm'
@@ -241,7 +241,7 @@ jobs:
         uses: actions/configure-pages@v5
 
       - name: Upload artifact
-        uses: actions/upload-pages-artifact@v3
+        uses: actions/upload-pages-artifact@v4
         with:
           path: site