### Summary

Our setuptools constrain in `pyproject.toml` (listed also in `setup.cfg`) is set to `>= 39.2.0` due to the minimum version available at the time on Ubuntu 18.04.

Now that we have a dependency on Python 3.9 as a minimum, that constraint no longer makes sense, as Python 3.9 is not available on 18.04, and the `dist-packages` `setuptools==39.2.0` compat between deadsnakes python3.9 is non-functional.

This would make Ubuntu 20.04 effectively the minimum supported controller.  The `dist-packages` `setuptools==45.2.0` is functional with the `python3.9` package, and works fine with our packaging.  

This doesn't really grant us anything, since we're waiting for the minimum to eventually be `51.0.0` so we can list the `entry_points` in `pyproject.toml`, but no need to list effectively a non-functional lower bounds. 

### Issue Type

Feature Idea

### Component Name

pyproject.toml

### Additional Information

<!--- Paste example playbooks or commands between quotes below -->
```yaml (paste below)

```


### Code of Conduct

- [X] I agree to follow the Ansible Code of Conduct
'setup.cfg',
        
        'docs/docsite/rst/dev_guide/testing/sanity/bin-symlinks.rst',
        'docs/docsite/rst/dev_guide/testing/sanity/botmeta.rst',
        'docs/docsite/rst/dev_guide/testing/sanity/integration-aliases.rst',
        'docs/docsite/rst/dev_guide/testing/sanity/release-names.rst',
    ))
    
    
    ignore_script = ('ansible-connection', 'ansible-test')
    manpages = ['docs/man/man1/ansible.1']
    for dirname, dummy, files in os.walk('bin'):
        for filename in files:
            if filename in ignore_script:
                continue
            manpages.append('docs/man/man1/%s.1' % filename)
    
    misc_generated_files = [
        'PKG-INFO',
    ]
    shipped_files = manpages + misc_generated_files
    for path in complete_file_list:
        if path not in ignore_files:
            for ignore in ignore_patterns:
                if fnmatch.fnmatch(path, ignore):
                    break
            else:
                shipped_files.append(path)
    return shipped_files
def assemble_files_to_install(complete_file_list):