Error at self-signed-ssl-server code sample on README

[tales-aparecida]

There's an error at https://github.com/joltup/rn-fetch-blob#self-signed-ssl-server

RNFetchBlob.config({
  trusty : true
})
.then('GET', 'https://mysite.com') // wrong line
.then((resp) => {
  // ...
})

should be

RNFetchBlob.config({
  trusty : true
})
.fetch('GET', 'https://mysite.com')
.then((resp) => {
  // ...
})

[Traviskn]

We would love to have a PR to update the README 😃

[tales-aparecida]

Here you go