message: fix: update CONTRIBUTING.md with nvm instructions
diff: @@ -60,6 +60,7 @@ You'll need the following:
  * [Git](https://git-scm.com/downloads)
  * [NodeJS](https://nodejs.org/en/download/)
  +* [Node Version Manager](https://github.com/nvm-sh/nvm)
  * [Yarn](https://classic.yarnpkg.com/en/docs/install)
  * [Docker](https://docs.docker.com/get-docker/)
  * [Docker Compose](https://docs.docker.com/compose/install/)
  @@ -74,6 +75,14 @@ cd optimism
  yarn install
  ```
  +### Install the Correct Version of NodeJS
  +
  +Using `nvm`, install the correct version of NodeJS.
  +
  +```
  +nvm use
  +```
  +
  ### Building the TypeScript packages
  To build all of the [TypeScript packages](./packages), run:
  