build(deps): bump nokogiri in /auth0_flutter/example/ios

Bumps [nokogiri](https://github.com/sparklemotion/nokogiri) from 1.19.1 to 1.19.4.
- [Release notes](https://github.com/sparklemotion/nokogiri/releases)
- [Changelog](https://github.com/sparklemotion/nokogiri/blob/main/CHANGELOG.md)
- [Commits](sparklemotion/nokogiri@v1.19.1...v1.19.4)

---
updated-dependencies:
- dependency-name: nokogiri
  dependency-version: 1.19.4
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

auth0_flutter/example/ios/Gemfile.lock

@@ -31,10 +31,10 @@ GEM
     mini_portile2 (2.8.9)
     minitest (5.27.0)
     nanaimo (0.3.0)
-    nokogiri (1.19.1)
+    nokogiri (1.19.4)
       mini_portile2 (~> 2.8.2)
       racc (~> 1.4)
-    nokogiri (1.19.1-x86_64-darwin)
+    nokogiri (1.19.4-x86_64-darwin)
       racc (~> 1.4)
     racc (1.8.1)
     rexml (3.4.2)