Support custom basePath

[raymondjacobson]

https://github.com/jup-ag/jupiter-quote-api-node/blob/main/src/index.ts#L20

In this code, basePath is overridden, though the types suggest you can pass your own

[raymondjacobson]

Workaround:

new SwapApi(
      new Configuration({
        basePath: 'http://localhost:3000/swap/v1'
      })
    )