Some devices, such as the LightBlue BTLE app on iOS, try to use Bluetooth 5
when connecting to a device. This means that they will send a
BLE_GAP_EVT_PHY_UPDATE_REQUEST message to shift to a new physical layer.
If this event isn't handled, LightBlue (and likely other Bluetooth 5.0
central devices) will try to connect and then fail, staying in
"Connecting..." state forever. This message should be replied to with
sd_ble_gap_phy_update, as documented in
drivers/bluetooth/s140_nrf52_6.1.1/s140_nrf52_6.1.1_API/include/ble_gap.h.
This commit handles the event. LightBlue can now successfully connect to a
BTLE device on a P10059 nRF52840 dongle running MicroPython. Two other
related events have logging added in case they are needed in the future.
30c7f1790b