Use weak features in Cargo.toml

[mulimoen]

Expands on the idea of @ajtribick in #204

[aldanor]

Rebase on master?

[aldanor]

MSRV fail?

[mulimoen]

We will have to bump msrv to use weak features. 1.60 was released 7th April 2022

[aldanor]

We will have to bump msrv to use weak features. 1.60 was released 7th April 2022

That's probably ok, simplifies maintenance going forward (whoever needs to use older rustc can always use the current crate version).

Probably makes sense to do a few more things:

• update the README (it mentions MSRV)
• list it in Cargo.toml of all crates (https://doc.rust-lang.org/cargo/reference/manifest.html#the-rust-version-field)
• bump the edition of all crates to 2021 (and mention it along with MSRV bump in the changelog)
• perhaps also change if any deps are outdated, idk? (parking_lot, mpi_sys, scopeguard, regex, etc... but maybe it could be a separate pr; lazy_static might even be thrown out in favor of once_cell...)

[mulimoen]

I updated the dependencies listed by cargo outdated

[mulimoen]

We could start using workspace inheritance as this has been stabilized

[mulimoen]

Rebased and cleared for review

[aldanor]

Probably worth adding an entry to the changelog.

(and another entry to Changed if we rename 'deprecated'->'no-deprecated')

[aldanor]

Ok, I think it should be good to go - I'll merge it when it's green 👍