add arm64 as per Elliot's

Author: alinelena

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

@@ -6,6 +6,9 @@ on:
 jobs:
   build:
     runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        architecture: [amd64, arm64]
     if: github.repository == 'stfc/janus-core'
     permissions:
       packages: write
@@ -29,5 +32,5 @@ jobs:
           file: ./containers/Dockerfile.marimo
           push: true
           tags: |
-            ghcr.io/stfc/janus-core/marimo:${{ github.sha }}
-            ghcr.io/stfc/janus-core/marimo:latest
+            ghcr.io/stfc/janus-core/marimo:${{ matrix.architecture }}-${{ github.sha }}
+            ghcr.io/stfc/janus-core/marimo:${{ matrix.architecture }}-latest