Getting latest version in `.galaxy_install_info`

[jjel...@containerstore.com]

Hi,

If I have a requirements.yml like this:

```

---

- name: abc

  src: g...@github.com:my-super-repo/ansible-abc.git

  scm: git

```

it will pull in the role and inside `meta/.galaxy_install_info` the contents will look like this:

```

{install_date: 'Tue Jan 30 16:59:06 2018', version: ''}

```

What I would like is to always pull in the latest git version in my `requirements.yml`, but I want to capture the version as the git sha instead of having it empty. Is there a good way to do this?