Add native-client feature

[MarcAntoine-Arnaud]

No description provided.

[Fishrock123]

Why?

[MarcAntoine-Arnaud]

Why?

To select backend with the native-client for every target, and don't need to play with features for targets...
Without that I need to wrote:

[target.'cfg(not(target_arch = "wasm32"))'.dependencies]
surf = { version = "2.1.0", default-features = false, features = ["curl-client"] }

[target.'cfg(target_arch = "wasm32")'.dependencies]
surf = { version = "2.1.0", default-features = false, features = ["wasm-client"] }

With that we will be able to wrote:

surf = { version = "2.1.0", default-features = false, features = ["native-client"] }