HTTPOptions body type does not allow FormData

[achingbrain]

The HTTPOptions type extends FetchOptions which extends RequestInit from electron-fetch, which has a body type of Stream | string | Blob | Buffer | null which does not include FormData.

In js-IPFS we transform multipart requests into FormData objects in the browser, which TS then says cannot be used with the http module exported by this module, since the types in electron-fetch say FormData is not a supported body type.

[lidel]

next steps are either:

• (a) PR electron-fetch
• (b) use types from something else
• (c) create our own types for fetch

(b) seems to be preferred way to tackle this

[achingbrain]

Fixed by #129