setting ELEPROX_EN instead of CL when enabling proximity detection

[simonsc-fl]

The case handling of the case CAL_LOCK_ENABLED_10_BIT_COPY in the function void MPR121_type::setCalibrationLock(mpr121_cal_lock_type lock) does set the bits for ELEPROX_EN instead of CL.

Currently bits are set like this:
ECR_backup |= (3<<4);

But shouldn't it be the following:
ECR_backup |= (3<<6);

https://github.com/BareConductive/mpr121/blob/89349589eb904063e1c95238abad658c2c9b0861/MPR121/MPR121.cpp#L621C1-L623C13