Dyn trait v2.7

[bacek]

Proposed quick fix for #414. I tested is with this:

    protoc_rust::run(protoc_rust::Args {
        input: &[...],
        includes: &[...],
        out_dir: "src/proto",
        customize: Customize {
            serde_derive: Some(true),
            dyn_trait: Some(true),
            ..Default::default()
        },
    })
    .expect("Failed to compile Protobuf definitions!");

[stepancheg]

Should work without option since df9780f.

[bacek]

It does.