pcg: make bincode as dev-dependency

[ignatenkobrain]

It is used only from #[test]s, so there is no need to have it in [dependencies].

This would help us a bit in Fedora since we package rust crates there.

[vks]

As far as I can tell, bincode is already a dev dependency:

rand/rand_pcg/Cargo.toml

Line 34 in 19d3baf

bincode = { version = "1", features = ["i128"] }

[ignatenkobrain]

Oh, I see..

It's just latest released version of pcg on crates.io doesn't have it. Would you mind releasing new version?

[vks]

Sorry for the late reply. This seems to be blocked by bincode-org/bincode#250.

[dhardy]

I'd prefer not to tweak this before that issue is fixed because we already had a couple of related issues.

[dhardy]

Okay, I made a PR against bincode: bincode-org/bincode#261

Motivation: the current version of PCG still uses rustc_version; it would be nice to get the next release out.