Update package.json

Drivetrain was renamed to differental_drive

Author: fgrossman

package.json

@@ -3,7 +3,7 @@
       ["XRPLib/__init__.py", "github:Open-STEM/XRP_Micropython/XRPLib/__init__.py"],
       ["XRPLib/board.py", "github:Open-STEM/XRP_Micropython/XRPLib/board.py"],
       ["XRPLib/defaults.py", "github:Open-STEM/XRP_Micropython/XRPLib/defaults.py"],
-      ["XRPLib/drivetrain.py", "github:Open-STEM/XRP_Micropython/XRPLib/drivetrain.py"],
+      ["XRPLib/differential_drive.py", "github:Open-STEM/XRP_Micropython/XRPLib/differential_drive.py"],
       ["XRPLib/encoded_motor.py", "github:Open-STEM/XRP_Micropython/XRPLib/encoded_motor.py"],
       ["XRPLib/encoder.py", "github:Open-STEM/XRP_Micropython/XRPLib/encoder.py"],
       ["XRPLib/motor.py", "github:Open-STEM/XRP_Micropython/XRPLib/motor.py"],