docs: add 4.x migration guide #284

	name: Lockfile checks

	on:
	push:
	branches: [main, 4.x]
	paths:
	- yarn.lock
	pull_request:
	# We want all branches so we configure types to be the GH default again
	types: [opened, synchronize, reopened]
	paths:
	- yarn.lock

	env:
	YARN_ENABLE_GLOBAL_CACHE: false

	jobs:
	lint_lockfile:
	name: Lint yarn.lock
	runs-on: ubuntu-latest
	steps:
	- name: Checkout sources
	uses: actions/checkout@v4
	- name: Get yarn cache directory path
	id: yarn-cache-dir-path
	run:
	echo "dir=$(corepack yarn config get cacheFolder)" >> $GITHUB_OUTPUT

	- uses: actions/cache@v4
	id: yarn-cache # use this to check for `cache-hit` (`steps.yarn-cache.outputs.cache-hit != 'true'`)
	with:
	path: ${{ steps.yarn-cache-dir-path.outputs.dir }}
	key: ${{ runner.os }}-yarn-${{ hashFiles('**/yarn.lock') }}
	restore-keys: \|
	${{ runner.os }}-yarn-
	- name: Install Node.js
	uses: actions/setup-node@v4
	with:
	node-version: lts/*
	- name: Install dependencies
	run: corepack yarn install --immutable --mode=skip-build

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