Environment variables don't appear to work in `ENTRYPOINT`. It is my understanding that the shell form of `ENTRYPOINT` will expand `ENV` variables at run time, but this doesn't to appear to work for `ENV_CONFIG_INT` in the example below. What have I done wrong in the following example?

*Dockerfile*

```
ENTRYPOINT [ "yarn", "run", "app-${ENV_CONFIG_INT}" ]

```

*Compose yaml*

```yaml
test:
    image: testimage/test:v1.0
    build:
        context: .
        dockerfile: Dockerfile
    env_file:
        - ./docker.env
    environment:
        - ENV_CONFIG_INT=1

```

**Error:**

```sh
error Command "app-${ENV_CONFIG_INT}" not found.

```

Replacing the value with a static int of say 1 fixes the issue, however I want the value to be dynamic at runtime.

Thanks in advance.