update dart version in docker container. #175

	name: build backend
	on: [push]
	jobs:
	build:
	runs-on: ubuntu-latest
	steps:
	- uses: actions/checkout@v2
	- name: Checkout submodules
	shell: bash
	run: \|
	auth_header="$(git config --local --get http.https://github.com/.extraheader)"
	git submodule sync --recursive
	git -c "http.extraheader=$auth_header" -c protocol.version=2 submodule update --init --force --recursive --depth=1
	- name: create build number
	id: buildnumber
	env:
	GIT_AUTHOR_NAME: 'Github Action CI'
	GIT_AUTHOR_EMAIL: 'herbert.github.ci@codeux.design'
	GIT_COMMITTER_NAME: 'Github Action CI'
	GIT_COMMITTER_EMAIL: 'herbert.github.ci@codeux.design'
	run: \|
	buildnumber=$(curl -s https://raw.githubusercontent.com/hpoul/git-buildnumber/v1.0/git-buildnumber.sh \| bash /dev/stdin generate)
	echo "::set-output name=buildnumber::$buildnumber"
	- name: docker build
	run: cd docker && docker-compose build backend
	- name: docker login and push
	run: \|
	echo '${{ secrets.CONTAINER_ACCESS_TOKEN }}' \| docker login https://containers.pkg.github.com -u ${{ secrets.CONTAINER_USER }} --password-stdin
	cd docker && docker-compose push backend
	- name: extract executable from image
	run: \|
	image=$( docker create containers.pkg.github.com/authpass/authpass-backend )
	docker cp ${image}:/authpass_backend.exe .
	docker rm ${image}
	- uses: actions/upload-artifact@v2
	with:
	name: auhpass_backend_${{ steps.buildnumber.outputs.buildnumber }}
	path: authpass_backend.exe

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