Bump actions/deploy-pages from 2 to 3 (G-Research#282)

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

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

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

.github/workflows/deploy-website.yml

@@ -90,4 +90,4 @@ jobs:
     steps:
       - name: Deploy to GitHub Pages
         id: deployment
-        uses: actions/deploy-pages@v2
+        uses: actions/deploy-pages@v3