Attempt to port to rustls 0.20

[mfelsche]

This is the continuation of #47 dressed up as a new PR. This is based on the heavy lifting done by @silverjam and some minor contributions by me.

This updates the certs used for testing as some were expired. I added a script based on openssl to regenerate the ones i updated. They are valid for 10 years.

This obsoletes #47

[NathanRoyer]

Thanks for your work; this allowed me to make mail-send work with async-std.

Is there anything blocking the merge?

[mfelsche]

I honestly don't know.

[silverjam]

Thanks for your work; this allowed me to make mail-send work with async-std.

Is there anything blocking the merge?

The main readme of this crate states that @skade is looking for a new maintainer (https://github.com/async-rs/async-tls/blob/master/README.md), so that's probably all that's blocking things.

[silverjam]

Maybe @dignifiedquire or @yoshuawuyts could help get this merged?

[Fishrock123]

@mfelsche Have you tried contacting Florian via the email in the maintenance notice? https://github.com/async-rs/async-tls#maintenance-notice

[dignifiedquire]

I will try to review latest next week

[dignifiedquire]

Thanks everyone, will cut a release tomorrow!

[silverjam]

Thank you @dignifiedquire!

[dignifiedquire]

Release 0.12.0 is out