Mitigate version mismatch of public rustls dependency

PyO3/maturin#1671

src/lib.rs

@@ -322,6 +322,18 @@ use std::convert::TryFrom;
 /// Re-exported http-crate.
 pub use http;
 
+/// Re-exported rustls crate
+///
+/// Use this re-export to always get a compatible version of `ClientConfig`.
+#[cfg(feature = "rustls")]
+pub use rustls;
+
+/// Re-exported native-tls crate
+///
+/// Use this re-export to always get a compatible version of `TlsConnector`.
+#[cfg(feature = "native-tls")]
+pub use native_tls;
+
 pub use body::{Body, BodyReader, BodyWithConfig};
 pub use config::{AgentConfig, Timeouts};
 use http::Method;