meta: use Yarn v3 instead of npm

[aduh95]

Introduce use of Yarn (Berry) instead of npm+lerna. It's recommended to use Corepack rather than downloading yarn directly. It's included with Node.js v16.x, or can be installed with npm install -g corepack on Node.js v14.x.

CI is passing, but there might be stuff to test before merging to ensure every thing keeps working. Main changes are:

• remove lerna as it looks like yarn workspaces cover all the use we had for it. we are keeping lerna for the releases for the time being.
• Replace npm commands by yarn ones in CI – except some in the endtoend test, e.g. create-react-app is still tested with npm as I believe it's the most common scenario.
• Replace use of file: protocol in package.jsons with Yarn's workspace: protocol.

Checkout https://yarnpkg.com/getting-started/migration for documentation regarding yarn's commands.

Notice: if running yarn --version in the root of this repo returns you something like 1.xx.xx, it means you have a yarn binary in your path that is not provided by Corepack. You should be able to run corepack yarn instead of yarn: corepack yarn --version always return 3.0.2.

Get started with the following commands:

corepack -v || npm i -g corepack # install Corepack if not already installed
yarn -v || corepack enable # install Yarn through Corepack if not already installed
yarn || corepack yarn install # install npm dependencies using yarn

[Murderlon]

Are we sure we can rid of lerna? We also depended on lerna for determining which packages were touched since the last release and what versions they will become. I'm not sure if that's in yarn workspaces as well?

[arturi]

@goto-bus-stop Renée, we could definitely use your expertise in reviewing this, please.

[goto-bus-stop]

Is there something specific you'd like me to look at? it high-level looks good to me, i'm not familiar with corepack or yarn 3.

[Murderlon]

A note in contributing.md would be good about Node 16x or manually installing corepack is required to run things locally.

[aduh95]

A note in contributing.md would be good about Node 16x or manually installing corepack is required to run things locally.

Added, PTAL.

Are we sure we can rid of lerna? We also depended on lerna for determining which packages were touched since the last release and what versions they will become. I'm not sure if that's in yarn workspaces as well?

I reverted this, we will explore replacing lerna with Yarn workspaces for releases in a follow up PR.