feat: adds new transaction substatus airdrop

Author: Insmael

src/main/java/com/cryptomarket/params/TransactionSubtype.java

@@ -21,7 +21,9 @@ public enum TransactionSubtype {
   /** chain switch from */
   CHAIN_SWITCH_FROM("CHAIN_SWITCH_FROM"),
   /** chain switch to */
-  CHAIN_SWITCH_TO("CHAIN_SWITCH_TO");
+  CHAIN_SWITCH_TO("CHAIN_SWITCH_TO"),
+  /** airdrop */
+  AIRDROP("AIRDROP");
 
   private final String label;
 

src/main/java/com/cryptomarket/sdk/websocket/CryptomarketWSWalletClient.java

@@ -9,7 +9,6 @@
 import com.cryptomarket.params.OrderBy;
 import com.cryptomarket.params.ParamsBuilder;
 import com.cryptomarket.params.Sort;
-import com.cryptomarket.params.SortBy;
 import com.cryptomarket.params.TransactionStatus;
 import com.cryptomarket.params.TransactionSubtype;
 import com.cryptomarket.params.TransactionType;