Update index.tsx

Author: fredrik0x

src/components/Banners/BugBountyBanner/index.tsx

@@ -10,7 +10,7 @@ const BugBountyBanner = () => (
     <Center>
       <p>
         The Ethereum Protocol Attackathon is live on Immunefi 
-         until the 25th of January, with up to $1,500,000 in rewards!
+         until the 25th of January, with up to USD 1,500,000 in rewards!
       </p>
     </Center>
   </BannerNotification>