Fix image source in contributor section

Updated image source in README.md.

Author: lordixir

README.md

@@ -97,7 +97,7 @@ Thanks go to these wonderful people
     <tr>
       <td align="center">
         <a href="https://github.com/ertugrulturan">
-          <img src="https://avatars.githubusercontent.com/u/60829297?v=4" width="100px;" alt=""/>
+          <img src="" width="100px;" alt=""/>
           <br />
           <sub>
             <b>Ertuğrul TURAN</b>