config.ru in capybara-webmock-0.6.0

- old
+ new

@@ -1,5 +1,5 @@
 require 'rack'
 require 'capybara/webmock/proxy'
 
 app = Capybara::Webmock::Proxy.new(Process.pid)
-Rack::Handler::WEBrick.run(app, Port: ENV.fetch('PROXY_PORT_NUMBER', 9292))
+Rack::Handler::WEBrick.run(app, Port: ENV.fetch('CAPYBARA_WEBMOCK_PROXY_PORT_NUMBER', 9292))