Use `Into<String>` or `ToString::to_string` rather than requiring owned `Strings` up front.

[gibbz00]

Partly a question if there's any reason why the API requires owned strings for constructors and such.

.add_scope(Scope::new("read".to_string()))
.add_scope(Scope::new("write".to_string()))

Could then become:

.add_scope(Scope::new("read"))
.add_scope(Scope::new("write"))

And the method signature would still make it clear that an allocation will take place.

This also applies to the oath2 crate.

[ramosbugs]

See ramosbugs/oauth2-rs#248. I'd be open to the constructor methods accepting impl Into<String> in both crates for better ergonomics.

[gibbz00]

Cool cool :) Might take a look at it when I have the time.