Apply suggestion from @tomaka

https://internals.rust-lang.org/t/pre-rfc-security-advisories-as-part-of-crates-io-metadata/4045/4

text/0000-security-advisories.md

@@ -13,11 +13,10 @@ same purpose and warn about vulnerable crate versions during compilation.
# Motivation
[motivation]: #motivation

When compared to other ecosystems such as Python's, Rust's packaging tooling
encourages many single-purpose crates instead of larger monoliths. This
situation, together with the strongly encouraged practice of pinning MINOR
versions of dependencies, slows down the propagation of critical security
fixes.
When compared to other ecosystems such as Python's, Rust's broader community
prefers many single-purpose crates over larger monoliths. This situation,
together with the strongly encouraged practice of pinning MINOR versions of
dependencies, slows down the propagation of critical security fixes.

Assume a crate `W`, which depends on `X`, which depends on `Y`, which depends
on `Z`.  If `Z` releases a new MINOR version including a security fix, it