<!--- 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

```

if os.path.isdir(b_search_path):
                            local_collection = CollectionRequirement.from_path(b_search_path, False)
                            break
                    if local_collection is None:
                        raise AnsibleError(message='Collection %s is not installed in any of the collection paths.' % collection_name)
                    
                    try:
                        remote_collection = CollectionRequirement.from_name(collection_name, apis, collection_version, False, parent=None)
                    except AnsibleError as e:
                        if e.message == 'Failed to find collection %s:%s' % (collection[0], collection[1]):
                            raise AnsibleError('Failed to find remote collection %s:%s on any of the galaxy servers' % (collection[0], collection[1]))
                        raise
                    download_url = remote_collection.metadata.download_url
                    headers = {}
                    remote_collection.api._add_auth_token(headers, download_url, required=False)
                    b_temp_tar_path = _download_file(download_url, b_temp_path, None, validate_certs, headers=headers)
                    local_collection.verify(remote_collection, search_path, b_temp_tar_path)
                except AnsibleError as err:
                    if ignore_errors:
                        display.warning("Failed to verify collection %s but skipping due to --ignore-errors being set. "
                                        "Error: %s" % (collection[0], to_text(err)))
                    else:
                        raise
@contextmanager
def _tempdir():
    b_temp_path = tempfile.mkdtemp(dir=to_bytes(C.DEFAULT_LOCAL_TMP, errors='surrogate_or_strict'))
    yield b_temp_path
    shutil.rmtree(b_temp_path)
@contextmanager
def _tarfile_extract(tar, member):