<!--- 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

```

self._verify_file_hash(b_collection_path, manifest_data['name'], expected_hash, modified_content)
        if modified_content:
            display.display("Collection %s contains modified content in the following files:" % to_text(self))
            display.display(to_text(self))
            display.vvv(to_text(self.b_path))
            for content_change in modified_content:
                display.display('    %s' % content_change.filename)
                display.vvv("    Expected: %s\n    Found: %s" % (content_change.expected, content_change.installed))
        else:
            display.vvv("Successfully verified that checksums for '%s:%s' match the remote collection" % (to_text(self), self.latest_version))
    def _verify_file_hash(self, b_path, filename, expected_hash, error_queue):
        b_file_path = to_bytes(os.path.join(to_text(b_path), filename), errors='surrogate_or_strict')
        if not os.path.isfile(b_file_path):
            actual_hash = None
        else:
            with open(b_file_path, mode='rb') as file_object:
                actual_hash = _consume_file(file_object)
        if expected_hash != actual_hash:
            error_queue.append(ModifiedContent(filename=filename, expected=expected_hash, installed=actual_hash))
    def _get_metadata(self):
        if self._metadata:
            return
        self._metadata = self.api.get_collection_version_metadata(self.namespace, self.name, self.latest_version)
    def _meets_requirements(self, version, requirements, parent):
        """
        Supports version identifiers can be '==', '!=', '>', '>=', '<', '<=', '*'. Each requirement is delimited by ','
        """
        op_map = {
            '!=': operator.ne,
            '==': operator.eq,