Advisories for Cargo/Vec-Const package

Affected versions of this crate claimed to construct a const Vec with nonzero length and capacity, but that cannot be done because such a Vec requires a pointer from an allocator. The implementation was later changed to just construct a std::borrow::Cow.

An issue was discovered in the vec-const crate before 2.0.0 for Rust. It tries to construct a Vec from a pointer to a const slice, leading to memory corruption.