envbuilder don't recognize "dockerComposeFile" param

Hi! My devcontainer.json looks like this:

```json
{
"name": "keycrm",
"dockerComposeFile": [
"../example.docker-compose.yml"
],
"service": "app",
"services": ["app", "db"],
"forwardPorts": [80],
"postAttachCommand": "service apache2 start",
"extensions": [
"felixfbecker.php-pack",
"cweijan.vscode-mysql-client2"
]
}
```

and coder don't recognize "dockerComposeFile" option. It's described in devcontainer.json schema, and supported by my IDE (phpstorm) as well. But when I'm trying to create a workspace with such devcontainer it usually fallback to default image.
So, maybee in future, would envbuilder support docker-compose files to build, or I'm using it in wrong way? I'm trying to make developer's workspace with standalone environment, but creating only "app" is not enough in case of no DB.

Comienza con el devcontainer.json proporcionado y ../example.docker-compose.yml, y luego rastrea cómo envbuilder gestiona la opción dockerComposeFile frente a su ruta de imagen predeterminada. Determina si los servicios app y db deben compilarse e iniciarse, y verifica que un workspace que use esta configuración ya no recurra a la imagen predeterminada.

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