Update build.yml, run with node 20 #264

	name: Build

	on: [push]

	jobs:
	HUGO_BUILD:
	name: Build website with Hugo
	runs-on: ubuntu-latest
	strategy:
	matrix:
	node: [ '12', '14', '16', '20' ]
	steps:
	- uses: actions/checkout@v2
	- uses: actions/setup-node@v2
	with:
	node-version: ${{ matrix.node }}
	- uses: actions/setup-python@v2
	with:
	python-version: '3.x'
	- uses: peaceiris/actions-hugo@v2
	with:
	hugo-version: '0.52'
	- name: Install jsonschema
	run: \|
	python -m pip install --upgrade pip
	pip install jsonschema
	- name: Install JS dependencies
	working-directory: ./themes/coopcycle
	run: \|
	npm ci
	npm run build
	npm prune
	- name: Build
	run: hugo
	- name: Validate JSON schema
	run: jsonschema --instance public/coopcycle.json coopcycle.schema

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