ci: add arm64 to base docker image platforms to build

.github/workflows/build-base-app.yml

@@ -5,16 +5,10 @@ on:
     branches:
       - 'main'
     paths:
-      - 'package.json'
-      - 'requirements.txt'
       - 'docker/base.Dockerfile'
 
   workflow_dispatch:
 
-env:
-  REGISTRY: ghcr.io
-  IMAGE_NAME: datatracker-app-base
-
 jobs:
   publish:
     runs-on: ubuntu-latest
@@ -25,12 +19,24 @@ jobs:
     steps:
     - uses: actions/checkout@v2
 
-    - name: Docker Build & Push
-      uses: mr-smithers-excellent/docker-build-push@v5.6
+    - name: Set up QEMU
+      uses: docker/setup-qemu-action@v2
+    
+    - name: Set up Docker Buildx
+      uses: docker/setup-buildx-action@v2
+
+    - name: Login to GitHub Container Registry
+      uses: docker/login-action@v2
       with:
-        image: ${{ env.IMAGE_NAME }}
-        tags: latest
-        registry: ${{ env.REGISTRY }}
-        dockerfile: docker/base.Dockerfile
+        registry: ghcr.io
         username: ${{ github.actor }}
         password: ${{ secrets.GITHUB_TOKEN }}
+
+    - name: Docker Build & Push
+      uses: docker/build-push-action@v3
+      with:
+        context: .
+        file: docker/base.Dockerfile
+        platforms: linux/amd64,linux/arm64
+        push: true
+        tags: ghcr.io/ietf-tools/datatracker-app-base:latest