Update README.md

Author: didarul-codes

README.md

@@ -54,6 +54,7 @@ xmlns:app="http://schemas.android.com/apk/res-auto"
         <attr name="boldText" format="boolean"/>
         <attr name="textSize" format="dimension"/>
         <attr name="progressColor" format="color"/>
+        <attr name="customFontFamily" format="reference"/>
         <attr name="background" format="reference"/>
         <attr name="progressBarSize" format="enum">
             <enum name="large" value="64"/>