When making a new config with a server.json file that exists and has {} as its contents, mdmctl fails

[devshowpass]

What version of micromdm are you using?

Built from repo

What micromdm command did you run?

mdmctl

What did you expect to see?

config set success (no response)

What did you see instead?

panic: assignment to entry in nil map

goroutine 1 [running]:
main.saveServerConfig(0xc0000e1df8, 0x7ffc5d66653d, 0x8, 0x1a, 0x0)
/home/peter/Work/micromdm/cmd/mdmctl/config.go:261 +0xc3
main.setCmd(0xc00001e0c0, 0x6, 0x6, 0x3, 0x0)
/home/peter/Work/micromdm/cmd/mdmctl/config.go:164 +0x2e6
main.(*configCommand).Run(0xc00000e048, 0xc00001e0b0, 0x7, 0x7, 0xc0000e1e01, 0xc00000e048)
/home/peter/Work/micromdm/cmd/mdmctl/config.go:62 +0xf5
main.(*configCommand).Run-fm(0xc00001e0b0, 0x7, 0x7, 0x6, 0xffffffffffffffff)
/home/peter/Work/micromdm/cmd/mdmctl/mdmdctl.go:28 +0x48
main.main()
/home/peter/Work/micromdm/cmd/mdmctl/mdmdctl.go:49 +0x185