Update community-meetups.json

Added ETHBelgium with a public calendar on Lu.ma

Author: exyzee

src/data/community-meetups.json

@@ -568,5 +568,11 @@
     "emoji": ":brazil:",
     "location": "São Paulo",
     "link": "https://lu.ma/user/erc55"
-  }       
+  }      
+   {
+    "title": "ETHBelgium ",
+    "emoji": ":belgium:",
+    "location": "Belgium",
+    "link": "https://lu.ma/ethbelgium"
+  }   
 ]