Symlink bypasses filesystem sandbox in wasmer

Wasmer is a web assembly (wasm) Runtime supporting WASIX, WASI and Emscripten. If the preopened directory has a symlink pointing outside, WASI programs can traverse the symlink and access host filesystem if the caller sets both `oflags::creat` and `rights::fd_write`. Programs can also crash the runtime by creating a symlink pointing outside with `path_symlink` and `path_open`ing the link. This issue has been addressed in commit `b9483d022` which has been included in release version 4.3.2. Users are advised to upgrade. There are no known workarounds for this vulnerability.