fix: Networks.fromInt must not return optional

Author: JeneaVranceanu

Sources/Web3Core/Structure/Event+Protocol.swift

@@ -77,7 +77,7 @@ public enum Networks {
 
     static let allValues = [Mainnet, Ropsten, Kovan, Rinkeby]
 
-    public static func fromInt(_ networkID: UInt) -> Networks? {
+    public static func fromInt(_ networkID: UInt) -> Networks {
         switch networkID {
         case 1:
             return Networks.Mainnet