v0.3.3

Added

• Added endpoints: playlists, search, shows, tracks, users.
• Client::from_refresh_token() method that allows you get a new client using an existing refresh token.
• Internal BoundedU32<const MIN: u32, const MAX: u32> type that clamps a u32 to MIN, MAX upon creation. Limit is a BoundedU32<1, 50> -
  what Spotify uses for its limits. u32s passed by users are converted to said type. This might be unpredictable behaviour for the users,
  but it will be documented and I believe it's for the better - however, I am open to suggestions and might remove it in the future.

Changed

• Methods with empty API responses now return Nil instead of (), in order to make deserialization from empty responses easy while keeping flexibility.