<!--- 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

```

tarinfo.mode = 0o0755 if tarinfo.isdir() else 0o0644
                    tarinfo.uid = tarinfo.gid = 0
                    tarinfo.uname = tarinfo.gname = ''
                    return tarinfo
                tar_file.add(os.path.realpath(b_src_path), arcname=filename, recursive=False, filter=reset_stat)
        shutil.copy(b_tar_filepath, b_tar_path)
        collection_name = "%s.%s" % (collection_manifest['collection_info']['namespace'],
                                     collection_manifest['collection_info']['name'])
        display.display('Created collection for %s at %s' % (collection_name, to_text(b_tar_path)))
def find_existing_collections(path):
    collections = []
    b_path = to_bytes(path, errors='surrogate_or_strict')
    for b_namespace in os.listdir(b_path):
        b_namespace_path = os.path.join(b_path, b_namespace)
        if os.path.isfile(b_namespace_path):
            continue
        for b_collection in os.listdir(b_namespace_path):
            b_collection_path = os.path.join(b_namespace_path, b_collection)
            if os.path.isdir(b_collection_path):
                req = CollectionRequirement.from_path(b_collection_path, False)
                display.vvv("Found installed collection %s:%s at '%s'" % (to_text(req), req.latest_version,
                                                                          to_text(b_collection_path)))
                collections.append(req)
    return collections
def _build_dependency_map(collections, existing_collections, b_temp_path, apis, validate_certs, force, force_deps,