[Pkg-rust-maintainers] Please backport rust 1.45.0 for python cryptography

[Chris Hofstaedtler]

Dear Rust maintainers,

python's cryptography library has recently (in 3.4) started using
Rust internally, however the code and crates used require 1.45.0 or
newer.

As I rebuild python libs on stable, it would be a lot easier if Rust
1.45.0+ would be available in backports.

Thanks for considering it,
Chris