next.js

428342db - Add `--use-yarn` flag to `create-next-app` (#49407)

Add `--use-yarn` flag to `create-next-app` (#49407) # Add `--use-yarn` flag to `create-next-app` fixes #49405 - [x] Implement `--use-yarn` flag - [x] Update docs - [x] Add tests Co-authored-by: Tobias Koppers <tobias.koppers@googlemail.com>