try to fix submodule

firmware/lib/Arduino-FOC-drivers/src/encoders/ma730/README.md

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+# MA730 SimpleFOC driver
+
+While MA730 absolute position magnetic rotary encoder is supported by the standard MagneticSensorSPI driver included in the base distribution, this MA730-specific driver includes some optimisations:
+
+- access to the other registers of the MA730
+- this driver directly reads the angle with one call to SPI
+- this will halve the number of 16-bit SPI transfers per simpleFOC loop iteration
+
+
+## Hardware setup
+
+Connect as per normal for your SPI bus. No special hardware setup is needed to use this driver.
+
+## Software setup
+
+Its actually easier to use than the standard SPI sensor class, because it is less generic:
+
+```c++
+#include "Arduino.h"
+#include "Wire.h"
+#include "SPI.h"
+#include "SimpleFOC.h"
+#include "SimpleFOCDrivers.h"
+#include "encoders/ma730/MagneticSensorMA730.h"
+
+#define SENSOR1_CS 5 // some digital pin that you're using as the nCS pin
+MagneticSensorMA730 sensor1(SENSOR1_CS);
+
+
+void setup() {
+    sensor1.init();
+}
+```
+
+Set some options:
+
+```c++
+MagneticSensorMA730 sensor1(SENSOR1_CS, mySPISettings);
+```
+
+Use another SPI bus:
+
+```c++
+void setup() {
+    sensor1.init(&SPI2);
+}
+```
+
+Here's how you can use it:
+
+```c++
+    // update the sensor (only needed if using the sensor without a motor)
+    sensor1.update();
+
+    // get the angle, in radians, including full rotations
+    float a1 = sensor1.getAngle();
+
+    // get the velocity, in rad/s - note: you have to call getAngle() on a regular basis for it to work
+    float v1 = sensor1.getVelocity();
+
+    // get the angle, in radians, no full rotations
+    float a2 = sensor1.getCurrentAngle();
+
+    // get the raw 14 bit value
+    uint16_t raw = sensor1.readRawAngle();
+
+    // get the field strength
+    FieldStrength fs = sensor1.getFieldStrength();
+    Serial.print("Field strength: ");
+    Serial.println(fs);
+
+    // set pulses per turn for encoder mode
+    sensor1.setPulsesPerTurn(999); // set to 999 if we want 1000 PPR == 4000 CPR
+```