fix: record-and-playback/core/Gemfile to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-RUBY-NOKOGIRI-9510795
- https://snyk.io/vuln/SNYK-RUBY-NOKOGIRI-9510789

Author: snyk-bot

record-and-playback/core/Gemfile

@@ -26,7 +26,7 @@ gem 'journald-logger', '~> 3.0'
 gem 'jwt', '~> 2.2'
 gem 'locale', '~> 2.1'
 gem 'loofah', '~> 2.19.1'
-gem 'nokogiri', '~> 1.16.5'
+gem 'nokogiri', '~> 1.18.4'
 gem 'open4', '~> 1.3'
 gem 'rb-inotify', '~> 0.10'
 gem 'redis', '~> 4.1'