Feature: add rename field attribute

[MrMarble]

Hi, Thanks for this great crate!

I added the rename field attribute so you can rename one field to the value you want, like with serde(rename).

---

My use case for this is that I use structs for API queries using serde rename to serialize into camelCase but keeping snake_case for the struct names.

example

#[derive(Deserialize, Serialize, Clone, Debug, FieldNamesAsArray)]
struct UserView {
	#[serde(rename = "userID")]
	#[field_names_as_array(rename = "userID")]
	pub user_id: u64,
	#[serde(rename = "userName")]
	#[field_names_as_array(rename = "userName")]
	pub user_name: String,
	pub followers: u64,
}

fn get_user_view(user_id: u64) -> Result<UserView> {
	let fields = UserView::FIELD_NAMES_AS_ARRAY;

	let view = client.user.get(&fields)?;
	// ^ This will generate a query with the
	// following format https://example.org/user/id?include_fields=userID,userName,followers

	Ok(view)
}

[jofas]

Thank you very much for your PR!

[MrMarble]

I committed the changes directly on Github if that's okay, I can squash if needed

[jofas]

No need, thank you. Looks like the codecov action is broken at the moment, sorry about that. Do you need the 0.3.1 release with the rename attribute fast (i.e. today)? If not I'd have a look at the open issues and the actions before making the release, this repo hasn't seen much love recently. I'd get the release done later this week then.

[MrMarble]

No need, thank you. Looks like the codecov action is broken at the moment, sorry about that. Do you need the 0.3.1 release with the rename attribute fast (i.e. today)? If not I'd have a look at the open issues and the actions before making the release, this repo hasn't seen much love recently. I'd get the release done later this week then.

No rush, I'm using my git fork until the release is made so you can take your time.
Thanks!