Macro version_group_enum

macro_rules! version_group_enum {
    ($(#[$attr:meta])* enum $id:ident { $($body:tt)* }) => { ... };
    ($(#[$attr:meta])* pub enum $id:ident { $($body:tt)* }) => { ... };
    ($(#[$attr:meta])* pub ($($vis:tt)+) enum $id:ident { $($body:tt)* }) => { ... };
}

Create an enum that maps an entry to a VersionGroupURI<T>

version_group_enum! {
    #[derive(Serialize, Deserialize)]
    enum Versions {
        V1 as "v1" => "my.api_group:1.0.0",
        V2 as "v2" => "my.second.api_group:1.2.0",
    }
}