Advisories for Cargo/Simple-Slab package

An issue was discovered in the simple-slab crate before 0.3.3 for Rust. index() allows an out-of-bounds read.

An issue was discovered in the simple-slab crate before 0.3.3 for Rust. remove() has an off-by-one error, causing memory leakage and a drop of uninitialized memory.