message: docs: add "ivy" and "zone.js" to known scopes in contributing guide
  Currently the contributing guide misses entries for the `ivy` and `zone.js`
  scopes. This commit adds these to the contributing guide as it is useful
  for new contributors to know which scopes are supported.
  PR Close
diff: @@ -222,6 +222,7 @@ The following is the list of supported scopes:
  * **router**
  * **service-worker**
  * **upgrade**
  +* **zone.js**
  There are currently a few exceptions to the "use package name" rule:
  @@ -231,6 +232,7 @@ There are currently a few exceptions to the "use package name" rule:
  * **changelog**: used for updating the release notes in CHANGELOG.md
  * **docs-infra**: used for docs-app (angular.io) related changes within the /aio directory of the
  repo
  +* **ivy**: used for changes to the [Ivy renderer](https://github.com/angular/angular/issues/21706).
  * none/empty string: useful for `style`, `test` and `refactor` changes that are done across all
  packages (e.g. `style: add missing semicolons`) and for docs changes that are not related to a
  specific package (e.g. `docs: fix typo in tutorial`).
  