<!--- 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 -->

##### ISSUE TYPE
- Bug Report

##### COMPONENT NAME
<!--- Write the short name of the module, plugin, task or feature below, use your best guess if unsure -->
Setup module and facts about de Operating System is detecting ansible_os_family as "Pop!_OS".
This distribution is based on Ubuntu, so it should be "Debian" the desired result

##### ANSIBLE VERSION
<!--- Paste verbatim output from "ansible --version" between quotes -->
```
ansible 2.9.6
  config file = /etc/ansible/ansible.cfg
  configured module search path = ['/home/moucho/.ansible/plugins/modules', '/usr/share/ansible/plugins/modules']
  ansible python module location = /usr/lib/python3/dist-packages/ansible
  executable location = /usr/bin/ansible
  python version = 3.8.2 (default, Apr 27 2020, 15:53:34) [GCC 9.3.0]
```

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

##### OS / ENVIRONMENT
<!--- Provide all relevant information below, e.g. target OS versions, network device firmware, etc. -->
Pop!_OS 20.04 LTS

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

<!--- Paste example playbooks or commands between quotes below -->
<!--- HINT: You can paste gist.github.com links for larger files -->

##### EXPECTED RESULTS
<!--- Describe what you expected to happen when running the steps above -->
ansible_os_family: "Debian"

##### ACTUAL RESULTS
<!--- Describe what actually happened. If possible run with extra verbosity (-vvvv) -->
ansible_os_family: "Pop!_OS"
<!--- Paste verbatim command output between quotes -->

"""give fake content if it exists, otherwise pretend the file is empty"""
        data = default
        if fname in testcase['input']:
            
            print('faked %s for %s' % (fname, testcase['name']))
            data = testcase['input'][fname].strip()
        if strip and data is not None:
            data = data.strip()
        return data
    def mock_get_uname(am, flags):
        if '-v' in flags:
            return testcase.get('uname_v', None)
        elif '-r' in flags:
            return testcase.get('uname_r', None)
        else:
            return None
    def mock_file_exists(fname, allow_empty=False):
        if fname not in testcase['input']:
            return False
        if allow_empty:
            return True
        return bool(len(testcase['input'][fname]))
    def mock_platform_system():