launch Spectral without a defined ruleset , should use default ruleset

[LasneF]

User story.
As a developer, I can do validate an API quickly, so that I can ensure a first level of quality

Is your feature request related to a problem?
doing a quicky sanity check should be simple , trivial

Describe the solution you'd like
be able to launch spectral lint and it runs , it means having the defaults ruleset ... by default without the requirement to create a file
can be minimal , but enought for sanity check ,
otherwise can get painfull when we grab api from various location on PC , and not able to just launch a simple command line but need to remember the right location of the ruleset

here is just doing spectral lint myFile.yaml , no more to get basic feedback

Additional context
Add any other context or screenshots about the feature request here.