Docker compose mounted volumes empty

## Affected builder image

`gcr.io/cloud-builders-community/docker-compose`

## Expected Behavior

Current directory volumes mounted via `docker-compose.yml` to not be empty.

## Actual Behavior

Mounted volume is empty.

## Steps to Reproduce the Problem
`cloudbuild.yaml`
```
steps:

- name: 'docker.io/tomatosource/docker-compose'
id: test
args:
- 'up'
- '--force-recreate'
- '--abort-on-container-exit'
- '--exit-code-from'
- 'app'
timeout: '300s'
```

`docker-compose.yml`
```
version: '3.5'

services:
app:
image: golang:alpine
volumes:
- .:/foo
working_dir: /foo
command: ls
```

## Additional Info

Running locally via `cloud-build-local --config=cloudbuild.yaml --dryrun=false .`