Run openapiTS two times in row throws an Error

[mbelsky]

Hey,

I've found an interesting issue with openapiTS: adding one more call of this function in tests/remote-schema/remote-schema.test.ts makes it fails. You may try to run this and you with get the following error:

import path from "path";
import openapiTS from "../../src/index";

describe("remote $refs", () => {
  it("resolves remote $refs", async () => {
    // vvv Add this line vvv
    await openapiTS(path.join(__dirname, "spec", "spec.yml"));
    const types = await openapiTS(path.join(__dirname, "spec", "spec.yml"));
    expect(types).toEqual(`/**
 * This file was auto-generated by openapi-typescript.
 * Do not make direct changes to the file.
 */
… (content not changed)

The Error message: 🚏 version missing from schema; specify whether this is OpenAPI v3 or v2 https://swagger.io/specification