Bump nokogiri from 1.13.6 to 1.13.9 in /site

Bumps [nokogiri](https://github.com/sparklemotion/nokogiri) from 1.13.6 to 1.13.9.
- [Release notes](https://github.com/sparklemotion/nokogiri/releases)
- [Changelog](https://github.com/sparklemotion/nokogiri/blob/main/CHANGELOG.md)
- [Commits](https://github.com/sparklemotion/nokogiri/compare/v1.13.6...v1.13.9)

---
updated-dependencies:
- dependency-name: nokogiri
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>
diff --git a/site/Gemfile.lock b/site/Gemfile.lock
index 54b0611..e236c5e 100644
--- a/site/Gemfile.lock
+++ b/site/Gemfile.lock
@@ -101,7 +101,7 @@
     mini_portile2 (2.8.0)
     minitest (5.11.3)
     multi_json (1.13.1)
-    nokogiri (1.13.6)
+    nokogiri (1.13.9)
       mini_portile2 (~> 2.8.0)
       racc (~> 1.4)
     padrino-helpers (0.12.9)