Update to rust edition 2021

[ramsayleung]

Description

Update to Rust edition 202

Motivation and Context

Trying to close #275, by the way, as for this:

Try removing the build_map and build_json macros now that HashMap::from([(a,b), (c,d)]) is possible (only in case it looks great).

I think it's necessary to keep build_json and build_map macros, since the current optional semantics can't be replaced with the built-in HashMap::from method:

        let params = build_map! {
            optional "album_type": album_type.map(|x| x.as_ref()),
            optional "market": market.map(|x| x.as_ref()),
            optional "limit": limit.as_deref(),
            optional "offset": offset.as_deref(),
        };

Dependencies

None

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How has this been tested?

All CI checks should pass

Is this change properly documented?

I think it's not necessary to add this to CHANGELOG

Last but not least, Merry Christmas :-)

[marioortizmanero]

You forgot to edit the edition for the rest of the crates. We should probably add rust-version = "1.56" to the Cargo.toml while we're at it. And remove resolver = "2", since that's default now.

I think it's necessary to keep build_json and build_map macros, since the current optional semantics can't be replaced with the built-in HashMap::from method:

Oh, you're right, I completely forgot about that. Yeah, I'd rather keep the macros in that case.

Anyway, it might be better to wait a bit more, maybe until 1.58 is released?

Merry Christmas, Ramsay!

[ramsayleung]

You forgot to edit the edition for the rest of the crates. We should probably add rust-version = "1.56" to the Cargo.toml while we're at it. And remove resolver = "2", since that's default now.

Good point!

Anyway, it might be better to wait a bit more, maybe until 1.58 is released?

Sure, we could wait for 1.58

[marioortizmanero]

It's time to merge this for the next version :)