Fix types

[raing3]

Follow on from: #812

To fix the incorrect type file reference which was causing an issue with my usage of the library:

Could not find a declaration file for module 'swagger-typescript-api'. '<path>/node_modules/swagger-typescript-api/dist/lib.cjs' implicitly has an 'any' type.
  Try `npm i --save-dev @types/swagger-typescript-api` if it exists or add a new declaration (.d.ts) file containing `declare module 'swagger-typescript-api';`

1 import { generateApi, GenerateApiParams } from 'swagger-typescript-api';