$ update_xcode_plugins
This tool adds the missing UUIDs into the installed Xcode plug-ins so that they can be loaded by newer versions of Xcode.
You can choose to run it once or install a launch agent that will trigger the tool every time any of your installed plugins are modified or Xcode/Xcode-beta gets updated.
Install
$ gem install update_xcode_plugins
(if using system ruby: sudo gem install update_xcode_plugins)
Usage
In Terminal:
$ update_xcode_plugins

Other options
For a dry run,
$ update_xcode_plugins --dry-run

To install the launch agent,
$ update_xcode_plugins --install-launch-agent
or to uninstall the launch agent,
$ update_xcode_plugins --uninstall-launch-agent