message: Add WASI path_rename fix to changelog
diff: ### Fixed
  +- [#1764](https://github.com/wasmerio/wasmer/pull/1764) Fix bug in WASI `path_rename` allowing renamed files to be 1 directory below a preopened directory.
  +
  ## 1.0.0-alpha5 - 2020-11-06
  ### Added
  