Support for flycheck in Swagger 2/OpenAPI 3 buffers using Spectral.
This flycheck checker tries to find swagger: 2.0 or openapi: 3.* in a YAML buffer to determine whether the file is (probably) a Swagger or OpenAPI spec. If it is, it will run the spectral linter on the file contents and report errors, warnings, and info-level messages to the flycheck buffer.