2.0.0 Include Spectral OAS3.0x ruleset

With recent upgrades to spectral, it made sense to include the spectral 3.0.x ruleset, as that aligns with much of what's requires for AWS.

These rules can still be overridden if they're causing you false positives by adjusting your own rules.xml file - hence raising this as a major version in case for your implementation it has any undesired affects.