Add retry to upload release

[messense]

Fixes #62

[adrianinsaval]

anything holding this back?

[BoboTiG]

It would also help the https://github.com/BoboTiG/ebook-reader-dict project where we consistently hit those issues:

requests.exceptions.HTTPError: 403 Client Error: rate limit exceeded for url: ...

[svenstaro]

Sorry, I haven't taken a look at this yet. I'd like to get this merged. Do you fancy rebasing?