chore(deps-dev): bump nokogiri in /demos/jekyll-demo (#75)

Bumps [nokogiri](https://github.com/sparklemotion/nokogiri) from 1.16.5 to 1.18.3.
- [Release notes](https://github.com/sparklemotion/nokogiri/releases)
- [Changelog](https://github.com/sparklemotion/nokogiri/blob/v1.18.3/CHANGELOG.md)
- [Commits](sparklemotion/nokogiri@v1.16.5...v1.18.3)

---
updated-dependencies:
- dependency-name: nokogiri
  dependency-type: indirect
...

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

demos/jekyll-demo/Gemfile.lock

@@ -68,13 +68,13 @@ GEM
       rb-fsevent (~> 0.10, >= 0.10.3)
       rb-inotify (~> 0.9, >= 0.9.10)
     mercenary (0.4.0)
-    nokogiri (1.16.5-x86_64-linux)
+    nokogiri (1.18.3-x86_64-linux-gnu)
       racc (~> 1.4)
     parallel (1.22.1)
     pathutil (0.16.2)
       forwardable-extended (~> 2.6)
     public_suffix (4.0.7)
-    racc (1.7.3)
+    racc (1.8.1)
     rainbow (3.1.1)
     rb-fsevent (0.11.1)
     rb-inotify (0.10.1)