message: Update feature matrix
diff: @@ -6,6 +6,7 @@ Blocks of changes will separated by version increments.
  ## **[Unreleased]**
  +- [#817](https://github.com/wasmerio/wasmer/pull/817) Add document for tracking features across backends and language integrations, [docs/feature_matrix.md]
  - [#790](https://github.com/wasmerio/wasmer/pull/790) Fix flaky test failure with LLVM, switch to large code model.
  - [#788](https://github.com/wasmerio/wasmer/pull/788) Use union merge on the changelog file.
  - [#785](https://github.com/wasmerio/wasmer/pull/785) Include Apache license file for spectests.
  