Update nokogiri to version 1.18.8

Author: depfu[bot]

Gemfile.lock

@@ -216,9 +216,9 @@ GEM
     net-smtp (0.5.1)
       net-protocol
     nio4r (2.7.4)
-    nokogiri (1.18.6-arm64-darwin)
+    nokogiri (1.18.8-arm64-darwin)
       racc (~> 1.4)
-    nokogiri (1.18.6-x86_64-linux-gnu)
+    nokogiri (1.18.8-x86_64-linux-gnu)
       racc (~> 1.4)
     ostruct (0.6.1)
     parallel (1.27.0)