docker-compose.yml: unable to extend version: "2" file (with build definition)

[schulzp]

Issue Overview

Use docker-compose.yml file version: '2' with extends: file + service.

Expected Behaviour

Load service-definition from file referenced in services:extends:file taking version of that file into account.

Current Behaviour

Currently org.arquillian.cube.docker.impl.docker.compose.ContainerBuilder#extend assumes the referenced file is version: 1 with services definitions at root level (line 690).

Steps To Reproduce

1. create docker-compose-services.yml with version: "2"
2. create docker-compose-test.yml with version: "2" containing a service definition with extends:file: docker-compose-services.yml and extends:service:<extended-service-name>
3. create arquillian.xml with <extension name="docker"> and <property name="dockerContainersFile">docker-compose-test.yml</property>
4. write a simple arquillian test and launch it

Additional Information

<details>
    <dependency>
        <groupId>org.arquillian.cube</groupId>
        <artifactId>arquillian-cube-docker</artifactId>
        <version>1.17.1</version>
        <scope>test</scope>
    </dependency>
</details>