Bump nokogiri from 1.8.1 to 1.11.3 in /example_app

Bumps [nokogiri](https://github.com/sparklemotion/nokogiri) from 1.8.1 to 1.11.3.
- [Release notes](https://github.com/sparklemotion/nokogiri/releases)
- [Changelog](https://github.com/sparklemotion/nokogiri/blob/main/CHANGELOG.md)
- [Commits](sparklemotion/nokogiri@v1.8.1...v1.11.3)

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

Author: dependabot[bot]

example_app/Gemfile.lock

@@ -25,20 +25,22 @@ GEM
     metaclass (0.0.4)
     method_source (0.9.0)
     mini_mime (0.1.4)
-    mini_portile2 (2.3.0)
+    mini_portile2 (2.5.1)
     minitest (5.10.3)
     mocha (1.3.0)
       metaclass (~> 0.0.1)
     multipart-post (2.0.0)
     mustermann (1.0.1)
-    nokogiri (1.8.1)
-      mini_portile2 (~> 2.3.0)
+    nokogiri (1.11.3)
+      mini_portile2 (~> 2.5.0)
+      racc (~> 1.4)
     octokit (4.7.0)
       sawyer (~> 0.8.0, >= 0.5.3)
     pry (0.11.1)
       coderay (~> 1.1.0)
       method_source (~> 0.9.0)
     public_suffix (3.0.0)
+    racc (1.5.2)
     rack (2.2.3)
     rack-flash3 (1.0.5)
       rack