Upgrade `rustls` to 0.19

[jakubadamw]

The 0.20 upgrade of it would have been much more substantial with quite a few breaking changes, so this is not included.

[mfelsche]

Turns out we depend on this change with our usage of surf and http-client and would love to get this out with a new release. :heart:

[jakubadamw]

@Fishrock123 any chance we could get this in?

[halvors]

@Fishrock123 Bump?

[Fishrock123]

since this crate exposes rustls api this is a breaking change, requiring a major, and that makes it require effort and I am short on time these days