build(deps): bump nokogiri in /appengine/rails-hello_world

Bumps [nokogiri](https://github.com/sparklemotion/nokogiri) from 1.17.1 to 1.18.8.
- [Release notes](https://github.com/sparklemotion/nokogiri/releases)
- [Changelog](https://github.com/sparklemotion/nokogiri/blob/main/CHANGELOG.md)
- [Commits](sparklemotion/nokogiri@v1.17.1...v1.18.8)

---
updated-dependencies:
- dependency-name: nokogiri
  dependency-version: 1.18.8
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

appengine/rails-hello_world/Gemfile.lock

@@ -120,7 +120,7 @@ GEM
     net-smtp (0.4.0.1)
       net-protocol
     nio4r (2.7.0)
-    nokogiri (1.17.1)
+    nokogiri (1.18.8)
       mini_portile2 (~> 2.8.2)
       racc (~> 1.4)
     public_suffix (5.0.3)