fixup! Add Datadog APM tracing support

Author: carlhoerberg

src/amqproxy/cli.cr

@@ -67,7 +67,7 @@ class AMQProxy::CLI
     abort ex.message
   end
 
-  def apply_env_variables
+  def apply_env_variables # ameba:disable Metrics/CyclomaticComplexity
     @listen_address = ENV["LISTEN_ADDRESS"]? || @listen_address
     @listen_port = ENV["LISTEN_PORT"]?.try &.to_i || @listen_port
     @http_port = ENV["HTTP_PORT"]?.try &.to_i || @http_port