1.12.0.b1

This release mainly adds Sigfox and LoRa coexistency on the FiPy. There are some additional bug fixes included:

• esp32: LoRa+Sigfox coexistency on the FiPy.
• esp32: Allow pin interrupts to be triggered even when the cache is disabled.
• esp32: Do not allow timer alarms ISR to run with the cache disabled.
  Otherwise the CPU crashes when writing to flash and the interrupt triggers.
• esp32: Solve BLE hang when searching for services.
• esp32: Correct behaviour of Alarm.callback(None). The alarm is correctly cancelled now.
• modpycom.c/pulses_get(): prevent lock-up at long pulses. Thanks to @robert-hh.
• esp32: Use spi_flash_get_chip_size() to determine the flash size. Thanks to @robert-hh.