stork-agent --use-env-file flag does not work

An attempt to run the stork-agent with the switch pointing to a custom env file location fails:

$ ./stork-agent --env-file=../../../etc/agent.env --use-env-file
FATA[2023-11-06 13:44:31]             main.go:432   the '../../../etc/agent.env' environment file is invalid: cannot set 'STORK_AGENT_HOST=localhost' environment variable: no such flag -STORK_AGENT_HOST

I tested it both on Ubuntu and macOS. It works fine for the stork-server but we use a different CLI lib there. I am not sure it ever worked properly because we don't seem to have system tests for it.