Update Network.kt

Author: soaryong-c

suikotlin/src/main/java/io/cosmostation/suikotlin/model/Network.kt

@@ -1,7 +1,7 @@
 package io.cosmostation.suikotlin.model
 
 sealed class Network(val name: String, val rpcUrl: String, val faucetUrl: String) {
-    class Mainnet : Network("Mainnet", "https://sui-mainnet-us-1.cosmostation.io", "")
+    class Mainnet : Network("Mainnet", "https://sui-mainnet-us-2.cosmostation.io", "")
 
     class Devnet : Network("Devnet", "https://sui-devnet-kr-1.cosmostation.io", "https://faucet.devnet.sui.io")
 
@@ -10,4 +10,4 @@ sealed class Network(val name: String, val rpcUrl: String, val faucetUrl: String
     class Localnet : Network("Localhost", "http://127.0.0.1:9000", "http://127.0.0.1:9000")
 
     class Custom(name: String, rpcUrl: String) : Network(name, rpcUrl, "")
-}
+}