post_start command not supported in compose.yml

Using latest VSCode, adding a [post_create hook](https://docs.docker.com/compose/how-tos/lifecycle/) to compose.yml results in an error building devcontainer, for example:
```
    post_start:
      - command: echo Hello world
```
The cause seems to be that an old version of Docker Compose is used (2.27), even if system docker compose is up to date