chore(gemfile): update in line with Chef WS v25.13.7

Author: dafyddj

Gemfile

@@ -22,7 +22,6 @@ gem 'kitchen-docker', git: 'https://github.com/test-kitchen/kitchen-docker', ref
 gem 'kitchen-inspec', '3.0.0'
 gem 'kitchen-salt', '0.7.2'
 
-# Avoid the error 'pkeys are immutable on OpenSSL 3.0'
-gem 'net-ssh', '>= 7.0.0'
+gem 'net-ssh', '7.3.0'
 
-gem 'test-kitchen', '3.9.0'
+gem 'test-kitchen', '3.9.1'