Missing syslog support after go-kit upgrade

[djrodgerspryor]

What did you do?

Running consul_exporter with one of the log.format parameter examples from the docs:

./consul_exporter --log.format "logger:syslog?appname=bob&local=7"

What did you expect to see?

Logs sent to syslog

What did you see instead? Under which circumstances?

consul_exporter crashes:

consul_exporter: error: unrecognized log format "logger:syslog?appname=bob&local=7", try --help

Cause
I think this is caused by the change of logging library: #144

I can't see any easy way to configure the new library so send logs to syslog. Are there some secret environment variables now?

It looks like go-kit supports syslog output: https://github.com/go-kit/log/blob/main/syslog/syslog.go