Parse docker compose file correctly when version is not declared

[eddumelendez]

version is optional in compose file.

Supported compose files:

Example 1:

redis:
  image: redis:7-alpine

Example 2:

version: 2.0
services:
  redis:
    image: redis:7-alpine

Example 3:

services:
  redis:
    image: redis:7-alpine

Fixes #8109