Don't build for arm
Don't build for arm

Hopefully a temporary fix because jacobsa/crypto currently doesn't build on arm

LoRaWanSoFa/ttn,jvanmalder/ttn,TheThingsNetwork/ttn,mgranberry/ttn,jvanmalder/ttn,mgranberry/ttn,mgranberry/ttn,TheThingsNetwork/ttn,LoRaWanSoFa/ttn,jvanmalder/ttn,TheThingsNetwork/ttn