style: resolve style guide violations

Author: alfonsobries

src/main/java/org/arkecosystem/crypto/transactions/types/UsernameRegistration.java

@@ -50,4 +50,4 @@ public void deserialize(ByteBuffer buffer) {
         String utf8Username = new String(username);
         this.asset.username = utf8Username;
     }
-}
+}