Update dependency nokogiri to v1.18.9

Author: renovate[bot]

Gemfile.lock

@@ -111,9 +111,9 @@ GEM
       jekyll-sitemap (~> 1.3)
     minitest (5.18.0)
     multipart-post (2.4.1)
-    nokogiri (1.18.7-arm64-darwin)
+    nokogiri (1.18.9-arm64-darwin)
       racc (~> 1.4)
-    nokogiri (1.18.7-x86_64-linux-gnu)
+    nokogiri (1.18.9-x86_64-linux-gnu)
       racc (~> 1.4)
     octokit (4.25.1)
       faraday (>= 1, < 3)