title: Change fontsize of existing Label in Cocos2d-x
body: <p>I am using Cocos2d-x 3.8.</p>
  
  <p>I need to change the fontsize of a created TTF <code>Label</code>. Ie after it has been created, I need to change the fontsize. Not at creation. There is a way, right?</p>
  
  <p>There is a <code>setSystemFontSize()</code>, however it seems that if you set it, the font itself changes from whatever font you initialized the label with, to the system font. I can't take that.</p>
  
  <p>Is there a way?</p>