Bump actions/deploy-pages from 1 to 2 (#1240)

Bumps [actions/deploy-pages](https://github.com/actions/deploy-pages) from 1 to 2.
- [Release notes](https://github.com/actions/deploy-pages/releases)
- [Commits](https://github.com/actions/deploy-pages/compare/v1...v2)

---
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/docfx.yaml

@@ -53,4 +53,4 @@ jobs:
         path: doc/_site
     - name: Deploy to GitHub Pages
       id: deployment
-      uses: actions/deploy-pages@v1
+      uses: actions/deploy-pages@v2