chore: add vpn black friday as sponsor

Author: vkarpov15

index.pug

@@ -250,6 +250,9 @@ html(lang='en')
               <a href="https://www.casinotopp.net">
                 <img class="sponsor" src="https://images.opencollective.com/casino-topp/1dd399a/logo.png" style="height: 100px">
               </a>
+              <a href="https://vpnblackfriday.com/">
+                <img class="sponsor" src="https://images.opencollective.com/vpn-black-friday/2b3cf9c/logo.png" style="height: 100px">
+              </a>
             </div>
           </div>