chore: add link for arenaz discord (l2beat#10332)

Author: yyhrnk

packages/config/src/projects/arenaz/arenaz.ts

@@ -27,7 +27,10 @@ export const arenaz = opStackL2({
       bridges: ['https://bridge.arena-z.gg/', 'https://leagueofkingdoms.com/'],
       documentation: ['https://whitepaper.playersarena.foundation/arena-z'],
       explorers: ['https://explorer.arena-z.gg/'],
-      socialMedia: ['https://x.com/OfficialArenaZ'],
+      socialMedia: [
+        'https://x.com/OfficialArenaZ',
+        'https://discord.com/invite/arenaz-a2z',
+      ],
     },
   },
   hasSuperchainScUpgrades: true,