Add Docker build workflow

Author: DeDTihoN

.github/workflows/docker-build-secretvm.yml

@@ -67,7 +67,7 @@ jobs:
             app:
               image: ghcr.io/${{ steps.set_repo.outputs.REPO_NAME }}@sha256:${{ steps.push.outputs.IMAGE_HASH }}
               ports:
-                - '8000:8000'
+                - '8000'
           EOL
 
       - name: Commit docker-compose-secretvm.yaml