message: Add changelog entry for wasitest update
diff: ## **[Unreleased]**
  +- [#1300](https://github.com/wasmerio/wasmer/pull/1300) Add support for multiple versions of WASI tests: wasitests now test all versions of WASI.
  - [#1285](https://github.com/wasmerio/wasmer/pull/1285) Greatly improve errors in `wasmer-interface-types`
  - [#1283](https://github.com/wasmerio/wasmer/pull/1283) Workaround for floating point arguments and return values in `DynamicFunc`s.
  