Update Dockerfile and docker docs #1

	name: ci·docker

	on:
	pull_request:
	paths:
	- .github/Dockerfile

	concurrency:
	group: ci/docker/${{ github.ref }}
	cancel-in-progress: true

	permissions:
	contents: read
	packages: write

	jobs:
	build-and-test:
	runs-on: ubuntu-latest
	steps:
	- uses: actions/checkout@v4

	- uses: docker/setup-buildx-action@v3

	- name: docker/buildx
	run:
	docker buildx build
	--tags pkgxdev/pkgx
	--platform linux/amd64,linux/arm64
	--file .github/Dockerfile
	.github

	- run: \|
	echo <<EoD> Dockerfile
	FROM pkgxdev/pkgx
	RUN env +duf && duf
	RUN if which duf; then exit 1; fi
	EoD

	docker build --file Dockerfile .

	- run: \|
	echo <<EoD> Dockerfile
	FROM pkgxdev/pkgx
	RUN echo '{}' > package.json
	RUN dev && npm --version
	RUN if which npm; then exit 1; fi
	EoD

	docker build --file Dockerfile .

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