Fix: Added muti-platform directive to docker-build workflow

* Also add build tags based on release tag

Author: mrajagopal

.github/workflows/docker-build.yml

@@ -35,6 +35,7 @@ jobs:
           file: nginx-utils/Dockerfile
           push: true
           tags: ghcr.io/nginx/nginx-utils:latest
+          platforms: linux/amd64,linux/arm64
 
   # Step 5: Install Trivy for Vulnerability Scanning
       - name: Install Trivy and scan image for vulnerabilities