Bump reqwest version for compatibility with tokio 1.x

[ZackPierce]

As the title suggests, it would be great to be able to use eventsource within the context of a tokio 1.x world, so bumping the reqwest dependency to a version that uses tokio 1.x is the whole story here.

Thanks!

[nab-os]

It would be nice to merge this Is this possible ?

[mordamax]

@lluchs ^^