Fix: add missing type definition of batch http option

[KylinDC]

Hi, it looks like winston has support batch mode in HTTP Transport in recent release(#1970,

winston/lib/winston/transports/http.js

Line 41 in b2fde9d

this.batch = options.batch || false;

), but in the type definition file, it still not support do the batch HTTP related configuration.
In this pull request, I add batch HTTP related types in transports type definition file to support configuration.

[wbt]

Thanks @KylinDC!

[KylinDC]

My pleasure, thanks for bringing us such a wonderful library!