add CI job for Docker Hub build and push #1

	name: "Docker"

	on:
	push:
	branches:
	- 'master'

	jobs:
	docker:
	runs-on: ubuntu-latest
	strategy:
	matrix:
	variant: ["client", "server"]
	steps:
	-
	name: Set up QEMU
	uses: docker/setup-qemu-action@v2
	-
	name: Set up Docker Buildx
	uses: docker/setup-buildx-action@v2
	-
	name: Login to Docker Hub
	uses: docker/login-action@v2
	with:
	username: ${{ secrets.DOCKERHUB_USERNAME }}
	password: ${{ secrets.DOCKERHUB_TOKEN }}
	-
	name: Build and push
	uses: docker/build-push-action@v4
	with:
	file: ./Dockerfile.${{ matrix.variant }}
	tags: m13253/dns-over-https-${{ matrix.variant }}:latest
	push: true
	-
	name: Logout from Docker Hub
	uses: docker/login-action@v2
	if: always()
	with:
	logout: true

Provide feedback