build(deps-dev): bump github-pages from 221 to 222 in /docs

Bumps [github-pages](https://github.com/github/pages-gem) from 221 to 222.
- [Release notes](https://github.com/github/pages-gem/releases)
- [Commits](https://github.com/github/pages-gem/compare/v221...v222

)

---
updated-dependencies:
- dependency-name: github-pages
  dependency-type: direct:development
  update-type: version-update:semver-major
...
Signed-off-by: dependabot[bot] <support@github.com>

docs/Gemfile.lock

@@ -48,7 +48,7 @@ GEM
     ffi (1.15.4)
     forwardable-extended (2.6.0)
     gemoji (3.0.1)
-    github-pages (221)
+    github-pages (222)
       github-pages-health-check (= 1.17.9)
       jekyll (= 3.9.0)
       jekyll-avatar (= 0.7.0)