Create advisory for Rust miscomilation bug which affects aes-soft

[newpavlov]

See: rust-lang/rust#63791

[richardwhiuk]

Similarly, should there be an advisory for:

• Rust 1.45.0: Regression from 1.44 to 1.45 rust-lang/rust#74739

• Rust 1.41.0: https://blog.rust-lang.org/2020/02/27/Rust-1.41.1.html

In theory, these could cause security vulnerabilities?

[pinkforest]

For some reason aes-soft never got never got an advisory - or it's not there atm
RustCrypto/block-ciphers#51 (comment)

I started a wider discussion whether we should file advisories against Rustc - which we don't atm
#1353

We need to see if it is feasible to file advisories against Rustc first - Closing until that is resolved.