Consider deprecating this in favor of `futures-rustls`

[paolobarbolini]

This library seems to be a tokio-tls fork which hasn't been updated for a long while.

In the meantime, tokio-tls was split into tokio-native-tls, maintained by the tokio project, and tokio-rustls, which is maintained by the rustls team. tokio-rustls was then soft forked into futures-rustls, which in my opinion supersedes this library.

I'd argue this library should be deprecated and users of it should migrate to futures-rustls.