build(deps): bump nokogiri in /appengine/rails-hello_world (#1555)

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

Author: dependabot[bot]

appengine/rails-hello_world/Gemfile.lock

@@ -108,7 +108,7 @@ GEM
     matrix (0.4.2)
     method_source (1.0.0)
     mini_mime (1.1.5)
-    mini_portile2 (2.8.8)
+    mini_portile2 (2.8.9)
     minitest (5.25.4)
     net-imap (0.4.10)
       date
@@ -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)