fix(index.d.ts): make `port` option optional

[dev-itsheng]

In HTTP request, if the port is default (http -> 80, https -> 443), the port of url can be optional.

And in the source code, it also handles scenarios where port is undefined (or not defined).

So I think in this scene the config of port shouldn't be written, and I omit the port property in my own project and it works fine (with the TypeScript error of course).

I changed the definition of package and make it optional.