duty cycle range for DC motor

[michelco86]

https://github.com/hugocool24/RobotSM/blob/2bb54f8a0c097134e9c9f963a299fc74c9e3b94d/2018/main.ino#L166

dCycle = map(dCycle,0,255,minimumPWM,maximumPWM);

find the suitable values for minimumPWM and maximumPWM. currently minimumPWM is at 150 which makes the car get stuck when turning at maximum angle so this value needs to be increased some what. maximumPWM should be set at as fast as we dare to go :) (max value for this is 255)