GHSA-66p5-j55p-32r9 smallvec creates uninitialized value of any type

• crates.io smallvec: < 0.6.13 → fixed in 0.6.13

Affected versions of this crate called `mem::uninitialized()` to create values of a user-supplied type `T`. This is unsound e.g. if `T` is a reference type (which must be non-null and thus may not remain uninitialized). The flaw was corrected by avoiding the use of `mem::uninitialized()`, using `MaybeUninit` instead.