Update arena-hero project img link name

_projects/arena.md

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 layout: project
 title:  "ARENA: The Augmented Reality Edge Networking Architecture"
-image: "/img/projects/arena-arch-3.png"
+image: "/img/projects/arena-hero.jpg"
 priority: 1
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 Many have predicted the future of the Web to be the integration of Web content with the real-world through technologies such as augmented reality. This overlay of virtual content on top of the physical world, called the Spatial Web (in different contexts might be called AR Cloud, MetaVerse, Digital Twin), holds promise for dramatically changing the Internet as we see it today, and has broad application.