Bump nokogiri from 1.16.5 to 1.18.3 in /samples/rails/app

Bumps [nokogiri](https://github.com/sparklemotion/nokogiri) from 1.16.5 to 1.18.3.
- [Release notes](https://github.com/sparklemotion/nokogiri/releases)
- [Changelog](https://github.com/sparklemotion/nokogiri/blob/v1.18.3/CHANGELOG.md)
- [Commits](sparklemotion/nokogiri@v1.16.5...v1.18.3)

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

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

Author: dependabot[bot]

samples/rails/app/Gemfile.lock

@@ -138,7 +138,7 @@ GEM
     marcel (1.0.4)
     matrix (0.4.2)
     mini_mime (1.1.5)
-    mini_portile2 (2.8.6)
+    mini_portile2 (2.8.8)
     minitest (5.22.3)
     msgpack (1.7.2)
     mutex_m (0.2.0)
@@ -152,7 +152,7 @@ GEM
     net-smtp (0.5.0)
       net-protocol
     nio4r (2.7.1)
-    nokogiri (1.16.5)
+    nokogiri (1.18.3)
       mini_portile2 (~> 2.8.2)
       racc (~> 1.4)
     orm_adapter (0.5.0)
@@ -162,7 +162,7 @@ GEM
     public_suffix (5.0.5)
     puma (6.4.2)
       nio4r (~> 2.0)
-    racc (1.7.3)
+    racc (1.8.1)
     rack (3.0.10)
     rack-session (2.0.0)
       rack (>= 3.0.0)