Update rand dependency

[survived]

secp256k1 depends on rand ^0.6 which's not up-to-date, latest rand is v0.8.4 now. That would be nice to update it to ^0.8

[thomaseizinger]

I think we can at least go to 0.7 once MSRV is upped to 1.36 which should happen soon!

[elichai]

@thomaseizinger Rust 1.36 allows us to use 0.8.

I'll open today/tomorrow a PR updating this library to 1.36 and rust 2018, but @survived because this is an OSS project and it's a big change it might take some time before it will be merged and released.

[apoelstra]

I'd like to get the Taproot release(s) out for all these crates and then do a 2018 release after that.

So, yes, "a while", but it hopefully won't be super far in the future :)

[elichai]

CC #331

[0ndorio]

@elichai Thanks for your work. @apoelstra Is #331 currently blocked by any major issues or just through time concerns? Is there anything I could do to speed up the review/merge process?

[apoelstra]

@0ndorio just time concerns -- we want to merge all the taproot stuff first, then cut a release, then we can do 2018 stuff.

[tcharding]

rand has been updated, this can be closed.