Upgrade to yarn v4 with yarnPath #4

	# Workflow for building a Gatsby site
	#
	# To get started with Gatsby see: https://www.gatsbyjs.com/docs/quick-start/
	#
	name: Build Gatsby site

	on:
	# Runs on pull requests targeting the default branch
	pull_request:
	branches: ["main"]
	# Runs on commits to the default branch
	push:
	branches: ["main"]

	# Default to bash
	defaults:
	run:
	shell: bash

	jobs:
	# Build job
	build:
	runs-on: ubuntu-latest
	steps:
	- name: Checkout
	uses: actions/checkout@v4
	- name: Detect package manager
	id: detect-package-manager
	run: \|
	if [ -f "${{ github.workspace }}/yarn.lock" ]; then
	echo "manager=yarn" >> $GITHUB_OUTPUT
	echo "command=install" >> $GITHUB_OUTPUT
	exit 0
	elif [ -f "${{ github.workspace }}/package.json" ]; then
	echo "manager=npm" >> $GITHUB_OUTPUT
	echo "command=ci" >> $GITHUB_OUTPUT
	exit 0
	else
	echo "Unable to determine package manager"
	exit 1
	fi
	- name: Setup Node
	uses: actions/setup-node@v4
	with:
	node-version: "20"
	cache: ${{ steps.detect-package-manager.outputs.manager }}
	- name: Install dependencies
	run: ${{ steps.detect-package-manager.outputs.manager }} ${{ steps.detect-package-manager.outputs.command }}
	- name: Build with Gatsby
	env:
	PREFIX_PATHS: 'true'
	run: ${{ steps.detect-package-manager.outputs.manager }} run build

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