title: python terraform apply auto approve not working
body: <p>I have a python code that performs terraform plan and apply.</p>
  
  <pre><code>from python_terraform import *
  
  class terraform(object):
  
      @staticmethod
      def execute(action):
          print(action)
          tf = Terraform(
              working_dir='/Users/kheshav/PROJECTS/terraform/demo_supinfo/tf_files')
          approve = {"auto-approve": True}
          if action is "PLAN":
              """
              return_code, stdout, stderr = tf.plan(
                  capture_output=True)
              """
              tf.plan(no_color=IsFlagged, refresh=False, capture_output=True)
              return_code, stdout, stderr = tf.plan()
              print(stdout)
          elif action == "APPLY":
              return_code, stdout, stderr = tf.apply(
                  capture_output=True, auto_approve=True, **approve)
          elif action == "DESTROY":
              return_code, stdout, stderr = tf.destroy(
                  capture_output=True, auto_approve=True, **approve)
          elif action == "OUTPUT":
              stdout = tf.output(
                  capture_output=True)
          return stdout
  </code></pre>
  
  <p>The PLAN part works correctly however the apply part is waiting for a 'yes', even though I have specified <code>{auto-approve: True}</code>. For information am using python 3.7 and python-terraform module 0.10.1</p>
  
  <p>The apply part hangs and if i exit the script i get the following output:</p>
  
  <pre><code>Traceback (most recent call last):
    File "main.py", line 85, in &lt;module&gt;
      handle_command(command, channel)
    File "main.py", line 23, in handle_command
      response = terraform.execute("APPLY")
    File "/Users/kheshav/PROJECTS/terraform/demo_supinfo/chatbot/terraform.py", line 26, in execute
      print("APPLYING")
    File "/Users/kheshav/.pyenv/versions/demo_supinfo/lib/python3.7/site-packages/python_terraform/__init__.py", line 113, in apply
      return self.cmd('apply', *args, **option_dict)
    File "/Users/kheshav/.pyenv/versions/demo_supinfo/lib/python3.7/site-packages/python_terraform/__init__.py", line 299, in cmd
      out, err = p.communicate()
    File "/Users/kheshav/.pyenv/versions/3.7.3/lib/python3.7/subprocess.py", line 939, in communicate
      stdout, stderr = self._communicate(input, endtime, timeout)
    File "/Users/kheshav/.pyenv/versions/3.7.3/lib/python3.7/subprocess.py", line 1681, in _communicate
      ready = selector.select(timeout)
    File "/Users/kheshav/.pyenv/versions/3.7.3/lib/python3.7/selectors.py", line 415, in select
      fd_event_list = self._selector.poll(timeout)
  KeyboardInterrupt
  </code></pre>
  
  <p>Thank you</p>