message: link explaining plugins
diff: ## 3.1.0
  ### Extensions
  -Selenium IDE supports extensions now, more info [here](https://github.com)
  +Selenium IDE supports extensions now, more info [here](https://github.com/SeleniumHQ/selenium-ide/wiki/Getting-Started-with-Plugins)
  ### SIDE Runner
  Can now run project files [headlessly in command line](https://www.npmjs.com/package/selenium-side-runner)
  