4.2.0

1.Added support for RAK2246 spi version.
2.Fix the bug that the internet cannot be accessed after ppp0 redial.
3.install.sh can pass --help parameter to see more installation information.
4.Install the latest version of chirpstack by default.
5.gateway-version print more information.
6.gateway-config and gateway-version show the actual gateway_id.
7.Create a rak_ap file in the /boot directory to restore to ap mode.
8.Modify the global_conf.json file of 7246 to make the transmit power more accurate.
9.When there is no match for tx power, the nearest smaller power will be used.Semtech UDP (legacy) packet forwarder
10.Delete default DNS(8.8.8.8, 223.5.5.5), the gateway will use the DNS assigned by the router to which it is connected.
11.In case of GPS connection, automatically change the system time to GPS time.