update wordpress logo to svg (#287)

Author: Arhell

_includes/wp_hero.html

@@ -6,7 +6,7 @@
           <h1>
             <span class="quiet">Codeception for</span>
 
-            <img src="/images/frameworks/wordpress.png" alt="WordPress"></h1>
+            <img src="/images/frameworks/wordpress-logo.svg" alt="WordPress"></h1>
         </div>
       </div>
     </div>