<!--- Verify first that your issue is not already reported on GitHub -->
<!--- Also test if the latest release and devel branch are affected too -->
<!--- Complete *all* sections as described, this form is processed automatically -->

##### SUMMARY
<!--- Explain the problem briefly below -->
We publish semver collection (vyos.vyos:0.0.1-dev58) to ansible galaxy, however by default it seems ansible-galaxy client will not be able to find it. You must specific the version number directly to fetch it.

https://galaxy.ansible.com/vyos/vyos


EDIT:

This is working as expect, but it would be nice to Include:

   --pre                       Include pre-release and development versions. By default, ansible-galaxy only finds stable versions.

##### ISSUE TYPE
- Bug Report

##### COMPONENT NAME
<!--- Write the short name of the module, plugin, task or feature below, use your best guess if unsure -->
ansible-galaxy

##### ANSIBLE VERSION
<!--- Paste verbatim output from "ansible --version" between quotes -->
```paste below
ansible 2.9.1
```

##### CONFIGURATION
<!--- Paste verbatim output from "ansible-config dump --only-changed" between quotes -->
```paste below

```


##### STEPS TO REPRODUCE
<!--- Describe exactly how to reproduce the problem, using a minimal test-case -->

<!--- Paste example playbooks or commands between quotes below -->
```yaml
$ ansible-galaxy collection install vyos.vyos -p /tmp/11123
[WARNING]: The specified collections path '/tmp/11123' is not part of the configured Ansible collections paths '/home/pabelanger/.ansible/collections:/usr/share/ansible/collections'. The
installed collection won't be picked up in an Ansible run.

Process install dependency map
ERROR! Cannot meet requirement * for dependency vyos.vyos from source 'https://galaxy.ansible.com/api/'. Available versions before last requirement added: 
Requirements from:
	base - 'vyos.vyos:*'
(venv) [pabelanger@localhost openstack]$ ansible-galaxy collection install vyos.vyos:0.0.1-dev57 -p /tmp/11123
[WARNING]: The specified collections path '/tmp/11123' is not part of the configured Ansible collections paths '/home/pabelanger/.ansible/collections:/usr/share/ansible/collections'. The
installed collection won't be picked up in an Ansible run.

Process install dependency map
Starting collection install process
Installing 'vyos.vyos:0.0.1-dev57' to '/tmp/11123/ansible_collections/vyos/vyos'
```

<!--- HINT: You can paste gist.github.com links for larger files -->

##### EXPECTED RESULTS
<!--- Describe what you expected to happen when running the steps above -->
vyos.vyos collection to be found and installed

##### ACTUAL RESULTS
<!--- Describe what actually happened. If possible run with extra verbosity (-vvvv) -->

<!--- Paste verbatim command output between quotes -->
```paste below

```

license='license (GPL-2.0-or-later, MIT, etc)',
                role_name=obj_name,
                role_type=context.CLIARGS['role_type'],
                issue_tracker_url='http://example.com/issue/tracker',
                repository_url='http://example.com/repository',
                documentation_url='http://docs.example.com',
                homepage_url='http://example.com',
                min_ansible_version=ansible_version[:3],  
            ))
            obj_path = os.path.join(init_path, obj_name)
        elif galaxy_type == 'collection':
            namespace, collection_name = obj_name.split('.', 1)
            inject_data.update(dict(
                namespace=namespace,
                collection_name=collection_name,
                version='1.0.0',
                readme='README.md',
                authors=['your name <example@domain.com>'],
                license=['GPL-2.0-or-later'],
                repository='http://example.com/repository',
                documentation='http://docs.example.com',
                homepage='http://example.com',
                issues='http://example.com/issue/tracker',
                build_ignore=[],
            ))
            obj_path = os.path.join(init_path, namespace, collection_name)
        b_obj_path = to_bytes(obj_path, errors='surrogate_or_strict')
        if os.path.exists(b_obj_path):
            if os.path.isfile(obj_path):
                raise AnsibleError("- the path %s already exists, but is a file - aborting" % to_native(obj_path))