chore: add opencollective sponsors: top web design companies, casino top

Author: vkarpov15

index.pug

@@ -223,6 +223,15 @@ html(lang='en')
               <a href="https://vpngorilla.com/">
                 <img class="sponsor" src="https://images.opencollective.com/vpngorilla-com/ae76cc5/logo.png" style="height: 100px">
               </a>
+              <a href="https://medium.com/@niksundin/best-web-design-companies-1872e445775f">
+                <img class="sponsor" src="https://images.opencollective.com/top-web-design-agencies/d92d747/logo.png" style="height: 100px">
+              </a>
+              <a href="https://www.casinotop.com">
+                <img class="sponsor" src="https://images.opencollective.com/casinotop-com/10fd95b/logo.png" style="height: 100px">
+              </a>
+              <a href="https://www.casinotopp.net">
+                <img class="sponsor" src="https://images.opencollective.com/casino-topp/1dd399a/logo.png" style="height: 100px">
+              </a>
             </div>
           </div>