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

Bumps [nokogiri](https://github.com/sparklemotion/nokogiri) from 1.15.4 to 1.16.4.
- [Release notes](https://github.com/sparklemotion/nokogiri/releases)
- [Changelog](https://github.com/sparklemotion/nokogiri/blob/main/CHANGELOG.md)
- [Commits](sparklemotion/nokogiri@v1.15.4...v1.16.4)

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

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

auth0_flutter/example/ios/Gemfile.lock

@@ -15,15 +15,15 @@ GEM
     concurrent-ruby (1.2.2)
     i18n (1.14.1)
       concurrent-ruby (~> 1.0)
-    mini_portile2 (2.8.4)
+    mini_portile2 (2.8.6)
     minitest (5.19.0)
     nanaimo (0.3.0)
-    nokogiri (1.15.4)
+    nokogiri (1.16.4)
       mini_portile2 (~> 2.8.2)
       racc (~> 1.4)
-    nokogiri (1.15.4-x86_64-darwin)
+    nokogiri (1.16.4-x86_64-darwin)
       racc (~> 1.4)
-    racc (1.7.1)
+    racc (1.7.3)
     rexml (3.2.6)
     slather (2.7.4)
       CFPropertyList (>= 2.2, < 4)