Add multicast support to udp component (#8051)

esphome/config_validation.py

@@ -1168,6 +1168,15 @@ def ipv4address(value):
     return address
 
 
+def ipv4address_multi_broadcast(value):
+    address = ipv4address(value)
+    if not (address.is_multicast or (address == IPv4Address("255.255.255.255"))):
+        raise Invalid(
+            f"{value} is not a multicasst address nor local broadcast address"
+        )
+    return address
+
+
 def ipaddress(value):
     try:
         address = ip_address(value)