Change the Sonnet model to 5 (#187)

Author: a-akimov

mcp-client-ruby/client.rb

@@ -6,7 +6,7 @@
 require "mcp"
 
 class MCPClient
-  ANTHROPIC_MODEL = "claude-sonnet-4-5"
+  ANTHROPIC_MODEL = "claude-sonnet-5"
 
   def initialize
     @mcp_client = nil