Use cargo add instead of a toml snippet in README

[rnestler]

No description provided.

[direc85]

Related: I can't install env_logger = "0.10.0" because candidate versions include 0.9.3, 0.9.2, 0.9.1, ... so there seems to be something wrong with publishing the package.

[epage]

Sorry, somehow I lost track of this PR

Related: I can't install env_logger = "0.10.0" because candidate versions include 0.9.3, 0.9.2, 0.9.1, ... so there seems to be something wrong with publishing the package.

What version of Rust are you using? If its before 1.60, then that is below the MSRV for 0.10 and the reason you aren't getting a better error message is due to rust-lang/cargo#10623

[direc85]

Our project is stuck with 1.52, but the update was tried with current stable (1.68?) and that was the error message still. May be because of Cargo.toml has 2018 in it or something... Well, 0:9.3 it is for us, thanks for clarifying!

I noticed the release still shows 0.9.3 instead of 0.10.0, I think that's a lightweight tag instead?

[epage]

Thanks!