Update deny.toml to cargo-deny v0.4

[iliana]

#495 (comment)

v0.4.0 renamed Openssl to OpenSSL and may have made some changes involving license exceptions.

[jahkeup]

This highlights the need for a defined and consistent build/development environment for folks. I did a quick look around for a way to write down binary-crate dependencies in Cargo.toml and came up empty handed.

We should have an environment compatibility check or maybe at a minimum a dependency listing of "known working" versions for ourselves and other contributors.

[iliana]

Yeah, I would appreciate being able to lock what binaries are used to build in Cargo.lock. I don't think there's a reasonable way to do that quite yet but I'll see if I can try to find a workaround.

[iliana]

EmbarkStudios/cargo-deny#50
EmbarkStudios/cargo-deny#51
EmbarkStudios/cargo-deny#53

WIP branch: wip-cargo-deny-v0.4

[iliana]

v0.5.2 has all the documented issues we've had fixed, so it's perhaps time to pick this up again.