feat: add support for aarch64 images (#8)

Author: callms

.github/workflows/upgrade-aws.yml

@@ -59,7 +59,9 @@ jobs:
       - name: Login to Amazon ECR
         id: login-ecr
         uses: aws-actions/amazon-ecr-login@v1
-      - name: Build
-        run: docker build -t 983851922138.dkr.ecr.eu-central-1.amazonaws.com/tippecanoe:latest .
-      - name: Push
-        run: docker push 983851922138.dkr.ecr.eu-central-1.amazonaws.com/tippecanoe
+      - name: "Build & Push (amd64, arm64)"
+        run: |
+          docker buildx build \
+            --platform linux/amd64,linux/arm64 \
+            -t 983851922138.dkr.ecr.eu-central-1.amazonaws.com/tippecanoe:latest \
+            --push .