title: PyQt combo box change value of a label
body: <p>I'm using PyQt5 to make a UI to a project. </p>
  
  <p>I want to change the value of a label when the user changes the value of a combo box.</p>
  
  <p>Can anyone help me to find out wich method to use to 'trigger' the function that changes the value of the label ?</p>