post_start command not supported in compose.yml

[DarkWanderer]

Using latest VSCode, adding a post_create hook 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

[DarkWanderer]

I have realized I have created this in a wrong repository - apologies for that