Fix MSRV issues by re-releasing sha1, sha2, sha3, md5, and whirlpool

[newpavlov]

Closes #394
Closes #395
Closes #396
Closes #397
Closes #398

[striezel]

As mentioned in the linked issues: Thanks for the attempted fix here. 👍

Unfortunately, none of the issues was fixed in this pull request / by the new releases. The new releases still contain a resolver = "2" line in their generated Cargo.tomls:

• https://docs.rs/crate/md-5/0.10.3/source/Cargo.toml
• https://docs.rs/crate/sha1/0.10.3/source/Cargo.toml
• https://docs.rs/crate/sha2/0.10.4/source/Cargo.toml
• https://docs.rs/crate/sha3/0.10.3/source/Cargo.toml
• https://docs.rs/crate/whirlpool/0.10.3/source/Cargo.toml

I've adjusted the title of each correponding issue to reflect that the newer versions are affected, too.

[newpavlov]

Weird... I specifically used the latest stable toolchain (1.63) to do the publishing.

[newpavlov]

I guess resolver = "2" has leaked from the workspace Cargo.toml. I will temporarily remove it and will do re-releases again.

cc @tarcieri

[striezel]

I guess resolver = "2" has leaked from the workspace Cargo.toml. I will temporarily remove it and will do re-releases again.

Maybe.

Just for reference: resolver = "2" was added to the workspace Cargo.toml in dfcfb21 / PR #375