Custom port when running as consumer in proxymode

[Fukitsu]

Is your feature request related to a problem? Please describe.
I run mysterium in consumer mode and proxy mode with: --consumer --proxymode daemon
and every time I connect to a node the port on which mysterium listens changes

Describe the solution you'd like
I would like to have a flag to specify a single port on which mysterium listens. Something like: --proxy.port or --port

Describe alternatives you've considered
I've tried setting a custom port using --udp.ports but it seems to always expect a range of at least 20 ports while I only want it to listen on a specific static port

[adinetech]

This might work: myst connection up --proxy <port-number> <consumer-identity>