Keep on connection updated method

[philips77]

The following method:

Android-BLE-Library/ble/src/main/java/no/nordicsemi/android/ble/BleManagerHandler.java

Lines 2461 to 2465 in b01984e

	public void onConnectionUpdated(@NonNull final BluetoothGatt gatt,
	@IntRange(from = 6, to = 3200) final int interval,
	@IntRange(from = 0, to = 499) final int latency,
	@IntRange(from = 10, to = 3200) final int timeout,
	final int status) {

method was being removed by Proguard and R8 as it seems not being used. In fact, it overrides a hidden method in BluetoothGattCallback. Marking it as @Keep will solve the issue.