Restoring Docker build (#871)

GitHub Action based on https://github.com/usha-mandya/SimpleWhaleDemo/blob/master/.github/workflows/github_registry.yml

Everything on the master branch gets published as `:latest` and version tags (pattern `vx.y.z`) get published as `:x.y.z`

.github/workflows/build-container.yaml

@@ -0,0 +1,60 @@
+name: Building and publishing container
+on:
+  push:
+    branches:
+      - master
+    tags:
+      - "v*.*.*"
+  workflow_dispatch:
+
+
+jobs:
+  build_and_publish:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Prepare
+        id: prep
+        run: |
+          DOCKER_IMAGE=openwpm/openwpm
+          TAGS="${DOCKER_IMAGE}:${GITHUB_SHA}"
+          # If it's a tagged build it should get published as such
+          if [[ $GITHUB_REF == refs/tags/v* ]]; then
+            VERSION=${GITHUB_REF#refs/tags/v}
+            TAGS="$TAGS,${DOCKER_IMAGE}:$VERSION"
+          fi
+          # If it is on master it should get tagged as latest
+          if [[ $GITHUB_REF == refs/heads/master ]]; then
+              TAGS="$TAGS,${DOCKER_IMAGE}:latest"
+          fi
+          echo ::set-output name=tags::${TAGS}
+
+      - name: Checkout
+        uses: actions/checkout@v2
+      - name: Set up Docker Buildx
+        id: buildx
+        uses: docker/setup-buildx-action@v1
+      - name: Cache Docker layers
+        uses: actions/cache@v2
+        with:
+          path: /tmp/.buildx-cache
+          key: ${{ runner.os }}-buildx-${{ github.sha }}
+          restore-keys: |
+            ${{ runner.os }}-buildx-
+      - name: Log into Dockerhub
+        uses: docker/login-action@v1 
+        with:
+          username: ${{ secrets.DOCKERHUB_USER_NAME }}
+          password: ${{ secrets.DOCKERHUB_USER_PASSWORD }}
+      - name: Build and push
+        id: docker_build
+        uses: docker/build-push-action@v2
+        with:
+          context: ./ 
+          file: ./Dockerfile
+          builder: ${{ steps.buildx.outputs.name }}
+          push: true
+          tags: ${{ steps.prep.outputs.tags }}
+          cache-from: type=local,src=/tmp/.buildx-cache
+          cache-to: type=local,dest=/tmp/.buildx-cache
+      - name: Image digest
+        run: echo ${{ steps.docker_build.outputs.digest }}