Is there a possibility of adding support for a 12th axis or slider?

**Describe your feature request**
Is there a possibility of adding support for a 12th axis or slider?
I have a 12-axis project, and this library works great up to 11 axes. Any easy way to add support for just one more?
**Additional context**
Arduino Leo connected to a ubuntu (Oro MacOS) machine running chrome/electron using the JS gamepad support

thanks for the amazing library!