Rename `docker-compose.yml` to `compose.yaml`

[wcbing]

The default path for a Compose file is compose.yaml (preferred), but the templates are docker-compose.yml

The default path for a Compose file is compose.yaml (preferred) or compose.yml that is placed in the working directory. Compose also supports docker-compose.yaml and docker-compose.yml for backwards compatibility of earlier versions. If both files exist, Compose prefers the canonical compose.yaml.
https://docs.docker.com/compose/intro/compose-application-model/#the-compose-file

[dbreshears]

@bwateratmsft, can you take a look at this. Seems reasonable

[bwateratmsft]

This is now released in Container Tools 2.1.0. Thanks again for the contribution @wcbing!