Update the base image to Ubuntu 20.04 so that it could be used for both amd64 and arm64 images

Set localtime to UTC so that the installation of tzdata do not ask for
selection.

Signed-off-by: Martin Tzvetanov Grigorov <[email protected]>

Author: martin-g

.github/workflows/docker-image-upload.yml

@@ -0,0 +1,56 @@
+name: Upload Docker images
+
+permissions:
+  packages: write      
+
+on:
+  push:
+    branches:
+      - 'master'
+
+jobs:
+  docker:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v1
+        with:
+          platforms: arm64
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v1
+
+      - name: Login to Github Docker Registry
+        uses: docker/login-action@v1 
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Set variables
+        id: vars
+        run: echo "::set-output name=date_tag::$(date +%y%m%d-%H%M)"
+
+      - name: Docker Buildx Create
+        run: docker buildx create --use
+
+      - name: Build and push build-su2
+        uses: docker/build-push-action@v2
+        with:
+          context: build
+          push: true
+          tags: ghcr.io/${{ github.repository_owner }}/su2code/build-su2:${{ steps.vars.outputs.date_tag }}
+          platforms: linux/amd64,linux/arm64
+
+      - name: Build and push test-su2
+        uses: docker/build-push-action@v2
+        with:
+          context: test
+          push: true
+          build-args: |
+            BASE_IMAGE=ghcr.io/${{ github.repository_owner }}/su2code/build-su2:${{ steps.vars.outputs.date_tag }}
+          tags: ghcr.io/${{ github.repository_owner }}/su2code/test-su2:${{ steps.vars.outputs.date_tag }}
+          platforms: linux/amd64,linux/arm64

build/Dockerfile

@@ -1,6 +1,11 @@
-FROM ubuntu:18.04
+FROM ubuntu:20.04
+
+LABEL org.opencontainers.image.source https://github.com/su2code/Docker-Builds
+
 ENV LANG C.UTF-8
-RUN apt-get update && apt-get install -y \
+RUN ln -fs /usr/share/zoneinfo/UTC /etc/localtime
+RUN DEBIAN_FRONTEND=noninteractive apt update && apt install -y \
+    apt-utils \
     python3 \
     pkg-config \
     python3-pip \

test/Dockerfile

@@ -1,4 +1,8 @@
-FROM su2code/build-su2:latest
+ARG BASE_IMAGE=su2code/build-su2:latest
+
+FROM $BASE_IMAGE
+
+LABEL org.opencontainers.image.source https://github.com/su2code/Docker-Builds
 
 # Copies your code file from your action repository to the filesystem path `/` of the container
 COPY runTests.sh /runTests.sh