[bytecodealliance/lucet] Release 0.4.3 - 0.4.3 crates.io release

DRANK

- Backported the fix for a memory corruption bug that could arise in certain runtime configurations. ([PR](https://github.com/bytecodealliance/lucet/pull/401)) ([RustSec advisory](https://rustsec.org/advisories/RUSTSEC-2020-0004.html))