swagger23 0.1.0

swagger23 converts Swagger 2.0 (OAS 2) API specifications into OpenAPI 3.0.3 (OAS 3) specifications. Accepts JSON or YAML input, produces JSON or YAML output. Works as a Ruby library (Swagger23.convert) or a standalone CLI tool (swagger23). Handles paths, parameters, requestBody, components/schemas, securitySchemes, servers, $ref rewriting, collectionFormat, x-nullable, discriminator, OAuth2 flows, and file uploads. No external runtime dependencies. Safe for large specs.