Update actions/cache action to v4 #341

	name: PR CI build

	on:
	pull_request: {}

	jobs:
	build:
	runs-on: ubuntu-latest

	env:
	CI: true
	NODE_OPTIONS: --max-old-space-size=4096

	steps:
	- uses: actions/checkout@v3

	# Beginning of yarn setup
	- name: use node.js 18.x
	uses: actions/setup-node@v3
	with:
	node-version: 18.x
	registry-url: https://registry.npmjs.org/ # Needed for auth
	- name: cache all node_modules
	id: cache-modules
	uses: actions/cache@v4
	with:
	path: '**/node_modules'
	key: ${{ runner.os }}-node_modules-${{ hashFiles('yarn.lock', '**/package.json') }}
	- name: find location of global yarn cache
	id: yarn-cache
	if: steps.cache-modules.outputs.cache-hit != 'true'
	run: echo "dir=$(yarn config get cacheFolder)" >> $GITHUB_OUTPUT
	- name: cache global yarn cache
	uses: actions/cache@v4
	if: steps.cache-modules.outputs.cache-hit != 'true'
	with:
	path: ${{ steps.yarn-cache.outputs.dir }}
	key: ${{ runner.os }}-yarn-${{ hashFiles('yarn.lock') }}
	restore-keys: \|
	${{ runner.os }}-yarn-
	- name: yarn install
	run: yarn install --immutable
	# End of yarn setup

	- name: knip
	run: yarn knip

	- name: lint
	run: yarn backstage-cli repo lint

	- name: deprecations
	run: yarn backstage-cli repo list-deprecations

	- name: type checking and declarations
	run: yarn tsc:full

	- name: tests
	run: yarn backstage-cli repo test

	- name: docker build
	env:
	DOCKER_BUILDKIT: 1
	run: docker build -t example .

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