MSRV on `md-5` v0.10.2 and v0.10.3 is broken

[striezel]

When trying to build a project that depends on md-5 v0.10.2 with rustc 1.48, one gets error messages from cargo. This appears to be an instance of rust-lang/cargo#10954, which means the md-5 crate simply needs to be re-uploaded with stable cargo or a newer nightly cargo.

The error message is:

error: failed to download `md-5 v0.10.2`

Caused by:
  unable to get packages from source

Caused by:
  failed to parse manifest at `/root/.cargo/registry/src/github.com-1ecc6299db9ec823/md-5-0.10.2/Cargo.toml`

Caused by:
  feature `resolver` is required

  this Cargo does not support nightly features, but if you
  switch to nightly channel you can add
  `cargo-features = ["resolver"]` to enable this feature

[striezel]

@newpavlov: Thanks for the attempted fix in #399. 👍

Unfortunately, this issue is not fixed in md-5 v0.10.3, the new release still contains a resolver = "2" line in the generated Cargo.toml: https://docs.rs/crate/md-5/0.10.3/source/Cargo.toml
Error message is basically still the same as shown above, except with a newer version number.

[striezel]

The issues seems to be fixed by #401 / in md-5 v0.10.4.