Multi-platform Earthly build must be in a target

.github/workflows/image.yml

@@ -54,4 +54,4 @@ jobs:
           version: v0.7.0
       - name: Build
         run: |
-            earthly --platform=linux/amd64 --platform=linux/arm64 --push +image --IMAGE=${{ steps.prep.outputs.image }}
+            earthly --push +image-all --IMAGE=${{ steps.prep.outputs.image }}

Earthfile

@@ -37,4 +37,7 @@ image:
     COPY +build/llama-cli /llama-cli
     ENV MODEL_PATH=/model.bin
     ENTRYPOINT /llama-cli
-    SAVE IMAGE --push $IMAGE
+    SAVE IMAGE --push $IMAGE
+
+image-all:
+    BUILD --platform=linux/amd64 --platform=linux/arm64 +image