Merge pull request #62 from zhangxd6/master

fix the thumbnail for dotnet

content/en/docs/CommunityLeaders/EventHandbooks/_index.html

@@ -93,7 +93,7 @@ title = "Event Handbooks"
       </div>
       <div class="card border-primary-dark">
         <img
-          src="/docs/images/logos/docker301.png"
+          src="/docs/images/logos/dock-dotnet.png"
 		  class="card-img-top"
 		  draggable="false"
           style="padding: 2rem;"