[BUG] [DOCS] haproxyconn Module : typeError: a bytes-like object is required, not 'str'

Setup
haproxyctl-0.3.1 from pip3 install haproxyctl

Salt Version:
           Salt: 3000.3
 
Dependency Versions:
           cffi: Not Installed
       cherrypy: Not Installed
       dateutil: Not Installed
      docker-py: Not Installed
          gitdb: Not Installed
      gitpython: Not Installed
         Jinja2: 2.11.1
        libgit2: Not Installed
       M2Crypto: 0.35.2
           Mako: Not Installed
   msgpack-pure: Not Installed
 msgpack-python: 0.6.2
   mysql-python: Not Installed
      pycparser: Not Installed
       pycrypto: 2.6.1
   pycryptodome: Not Installed
         pygit2: Not Installed
         Python: 3.6.8 (default, Apr  2 2020, 13:34:55)
   python-gnupg: Not Installed
         PyYAML: 3.13
          PyZMQ: 15.3.0
          smmap: Not Installed
        timelib: Not Installed
        Tornado: 4.5.3
            ZMQ: 4.1.4
 
System Versions:
           dist: centos 7.8.2003 Core
         locale: UTF-8
        machine: x86_64
        release: 3.10.0-1127.8.2.el7.x86_64
         system: Linux
        version: CentOS Linux 7.8.2003 Core

Steps to Reproduce the behavior

salt-call --local haproxy.show_backends -l debug

[DEBUG   ] Reading configuration from /etc/salt/minion
[DEBUG   ] Including configuration from '/etc/salt/minion.d/_schedule.conf'
[DEBUG   ] Reading configuration from /etc/salt/minion.d/_schedule.conf
[WARNING ] The 'environment' minion config option has been renamed to 'saltenv'. Using dev as the 'saltenv' config value.
[DEBUG   ] Configuration file path: /etc/salt/minion
[WARNING ] Insecure logging configuration detected! Sensitive data may be logged.
[DEBUG   ] Grains refresh requested. Refreshing grains.
[DEBUG   ] Reading configuration from /etc/salt/minion
[DEBUG   ] Including configuration from '/etc/salt/minion.d/_schedule.conf'
[DEBUG   ] Reading configuration from /etc/salt/minion.d/_schedule.conf
[DEBUG   ] Loading static grains from /etc/salt/grains
[DEBUG   ] LazyLoaded zfs.is_supported
[DEBUG   ] Determining pillar cache
[DEBUG   ] LazyLoaded jinja.render
[DEBUG   ] LazyLoaded yaml.render
[DEBUG   ] pillarenv 'dev' not found in the configured pillar environments (base)
[DEBUG   ] LazyLoaded jinja.render
[DEBUG   ] LazyLoaded yaml.render
[DEBUG   ] LazyLoaded haproxy.show_backends
[DEBUG   ] LazyLoaded direct_call.execute

Passed invalid arguments: a bytes-like object is required, not 'str'.

Usage:

    Show HaProxy Backends

    socket
        haproxy stats socket, default ``/var/run/haproxy.sock``

    CLI Example:

    .. code-block:: bash

        salt '*' haproxy.show_backends
    
Traceback (most recent call last):
  File "/usr/lib/python3.6/site-packages/salt/cli/caller.py", line 218, in call
    ret['return'] = self.minion.executors[fname](self.opts, data, func, args, kwargs)
  File "/usr/lib/python3.6/site-packages/salt/executors/direct_call.py", line 12, in execute
    return func(*args, **kwargs)
  File "/usr/lib/python3.6/site-packages/salt/modules/haproxyconn.py", line 373, in show_backends
    return ha_conn.sendCmd(ha_cmd)
  File "/usr/local/lib/python3.6/site-packages/haproxy/conn.py", line 33, in sendCmd
    self.sock.send(cmd.getCmd())
TypeError: a bytes-like object is required, not 'str'

Start with salt/modules/haproxyconn.py at show_backends and the haproxy/conn.py sendCmd traceback shown in the report. Reproduce with salt-call --local haproxy.show_backends -l debug, then trace the command and socket interaction. Done means the command no longer raises the reported TypeError and returns the HAProxy backends.