fix: smtp_proxy_server hostname && add docker image for linux/arm64 (#180)

.github/workflows/smtp_proxy_server.yml

@@ -30,6 +30,9 @@ jobs:
           username: ${{ github.actor }}
           password: ${{ secrets.GITHUB_TOKEN }}
 
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v3
+
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v3
 
@@ -38,6 +41,7 @@ jobs:
         with:
           context: ./smtp_proxy_server
           file: ./smtp_proxy_server/dockerfile
+          platforms: linux/amd64,linux/arm64
           push: true
           tags: |
             ${{ env.REGISTRY }}/${{ github.repository }}/${{ env.IMAGE_NAME }}:${{ github.ref_name }}