New build gives error from time to time

Discussed in https://github.com/evcc-io/evcc/discussions/9423

^{Originally posted by **TheSpirit** August 18, 2023} HI, nachdem ich gerade den neusten master selbst gebaut habe bekomme ich bei zwei von drei Versuchen folgenden Fehler. Was kann das sein. Mit einem build von letzter Woche ist das nicht der Fall. ``` root@loxberry:/usr/local/bin# ./evcc charger [main ] INFO 2023/08/18 07:23:17 evcc 0.118.11 [main ] INFO 2023/08/18 07:23:17 using config file: /etc/evcc.yaml [mqtt ] INFO 2023/08/18 07:23:18 connecting evcc-443770825 at tcp://192.168.178.48:1883 panic: runtime error: invalid memory address or nil pointer dereference [signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0xdbe280] goroutine 56 [running]: github.com/evcc-io/evcc/provider/mqtt.(*Client).Publish(0x0, {0x53267f4, 0xb}, 0x1, {0x1e666e8, 0x2a9a290}) github.com/evcc-io/evcc/provider/mqtt/client.go:123 +0x14 github.com/evcc-io/evcc/cmd.configureMQTT.func1.1({0x2b165dc, 0x4e34c00}) github.com/evcc-io/evcc/cmd/setup.go:454 +0x78 created by github.com/eclipse/paho%2emqtt%2egolang.(*client).startCommsWorkers in goroutine 51 github.com/eclipse/paho.mqtt.golang@v1.4.2/client.go:615 +0x5a4 ```

evcc-io / evcc

New build gives error from time to time #9424

Discussed in https://github.com/evcc-io/evcc/discussions/9423