Add `--filenames-only` argument to cli

[benedikt-bartscher]

Add --filenames-only argument, which only prints filenames with violations to stdout

edit: we could also just add a reporter

[sbdchd]

Could you use the json reporter with jq?

❯ squawk --reporter=json example.sql | jq 'map(.file) | unique'
[
  "example.sql"
]

[benedikt-bartscher]

Yeah, that's what I ended up doing, thanks