add method for sha256 deserialization mappers

src/main/java/com/sparrowwallet/drongo/protocol/Sha256Hash.java

@@ -61,6 +61,18 @@ public class Sha256Hash implements Comparable<Sha256Hash> {
         return wrap(Utils.hexToBytes(hexString));
     }
 
+    /**
+     * Duplicate method with default name for deserialization mappers.
+     *
+     * @param hexString a hash value represented as a hex string
+     * @return a new instance
+     * @throws IllegalArgumentException if the given string is not a valid
+     *         hex string, or if it does not represent exactly 32 bytes
+     */
+    public static Sha256Hash fromString(String hexString) {
+        return wrap(hexString);
+    }
+
     /**
      * Creates a new instance that wraps the given hash value, but with byte order reversed.
      *