Klipper 13 compliant

[metzenw]

A recent commit in Klipper broke the tapchanger plugin solution. Folks have been reporting that downgrading to Klipper 12 works around these changes.

Based on that conversation, it seems like the plugin should be updated to be Klipper 13 compliant.

https://klipper.discourse.group/t/stealthchanger-tapchanger-tool-error/23097
Klipper3d/klipper#6879
https://www.reddit.com/r/VORONDesign/comments/1k3y11z/stealthchanger_tapchanger_tool_error/
https://imgur.com/6dxZewl