Update README.md (#3818)

Add corepack note

### Change Type

- [x] `docs` — Changes to the documentation, examples, or templates.
- [x] `improvement` — Improving existing features

README.md

@@ -37,6 +37,12 @@ The local development server will run our examples app. The basic example will s
 
 To run the local development server, first clone this repo.
 
+Enable [corepack](https://nodejs.org/api/corepack.html) to make sure you have the right version of `yarn`:
+
+```bash
+corepack enable
+```
+
 Install dependencies:
 
 ```bash