Bump actions/checkout from 3 to 4 #9

	name: Validate pull request

	on:
	pull_request:
	branches: [ 'master' ]

	jobs:
	buildx:
	runs-on: ubuntu-latest
	steps:

	- name: Get release version
	id: version_number
	shell: bash
	run: \|
	echo "RELEASE_VERSION=${GITHUB_REF:10}" >> $GITHUB_ENV
	echo "::set-output name=RELEASE_VERSION::${GITHUB_REF:10}"

	export BUILD_DATE=$(date -u +"%Y-%m-%dT%H:%M:%SZ")
	echo "BUILD_DATE=${BUILD_DATE}" >> $GITHUB_ENV
	echo "::set-output name=BUILD_DATE::${BUILD_DATE}"

	- name: Set up QEMU
	uses: docker/setup-qemu-action@v1

	- name: Set up Docker Buildx
	id: buildx
	uses: docker/setup-buildx-action@master
	with:
	install: true

	- name: Builder info
	run: \|
	echo "Name: ${{ steps.buildx.outputs.name }}"
	echo "Endpoint: ${{ steps.buildx.outputs.endpoint }}"
	echo "Status: ${{ steps.buildx.outputs.status }}"
	echo "Flags: ${{ steps.buildx.outputs.flags }}"
	echo "Platforms: ${{ steps.buildx.outputs.platforms }}"

	- name: Cache Docker layers
	uses: actions/cache@v2
	with:
	path: /tmp/.buildx-cache
	key: ${{ runner.os }}-single-buildx-${{ github.sha }}
	restore-keys: \|
	${{ runner.os }}-single-buildx-

	- name: Build Alpine
	uses: docker/build-push-action@v4
	with:
	context: .
	push: false
	tags: \|
	boky/alpine-bootstrap:latest
	boky/alpine-bootstrap:latest-alpine
	platforms: "linux/amd64" # linux/s390x: "rsyslog (no such package)"
	cache-from: type=local,src=/tmp/.buildx-cache/alpine

	build-args: \|
	ALPINE_VERSION=alpine:latest
	VCS_REF=${{ steps.version_number.outputs.RELEASE_VERSION }}
	BUILD_DATE=${{ steps.version_number.outputs.BUILD_DATE }}

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