TS types for oas-validator

[kibertoad]

Detailed Description

oas-validator is missing TS types, which makes consuming it from TS projects rather inconvenient.

We (Lokalise) can contribute the types, in case they would be accepted by the project.

[MikeRalphson]

Thank you for the kind offer. Would the types only cover the exported properties of the module, or all the internal objects (such as the OpenAPI Specification itself)?

Either way, please wait for the next major version before creating any PR as there have been a lot of unpublished changes.