Add RollTable Company Credit (agones-dev#2002)

Added rolltable as companies that use Agones. I was recommended to add
this to the company list from a comment on our companies blog article
here, https://medium.com/rolltableapp/scalable-game-servers-using-agones-node-and-digital-ocean-90e6fb9ee5d

Author: NullSoldier

site/content/en/_index.html

@@ -58,6 +58,7 @@ <h2 class="text-center pb-3">Companies using Agones</h2>
 		<a href="https://www.embark.games/"><img alt="Embark Studios" width="50" src="images/embark.png" /></a>
 		<a href="http://accelbyte.io/"><img alt="accelbyte" width="100" src="images/accelbyte.png" /></a>
 		<a href="https://space.game/"><img alt="Space Game" width="80" src="images/spacegame.png" /></a>
+		<a href="https://rolltable.app/"><img alt="rolltable" width="100" src="images/rolltable.png" /></a>
 	</p>
 </div>
 {{< /blocks/section >}}