add retry feature

[mnlbox]

Hi I'm using https://github.com/tiaanduplessis/tenacious-fetch and I think it's a good idea if we can support retry fetch here in react-native-offline-api.

@Exilz Are you agree?

[Exilz]

Yes this is a feature I plan to add later.

It won't be part of 3.0 though.

[mnlbox]

@Exilz Any news or roadmap?

[Exilz]

I couldn't take a look at it yet. This is definitely the top priority feature once I start working on it.

No ETA though, sorry.