Fix HDKey type

Author: alcuadrado

src/pure/hdkey.ts

@@ -5,8 +5,8 @@ export interface Versions {
 
 export declare class HDKeyT {
   public static HARDENED_OFFSET: number;
-  public static fromMasterSeed(seed: Buffer, versions: Versions): HDKeyT;
-  public static fromExtendedKey(base58key: string, versions: Versions): HDKeyT;
+  public static fromMasterSeed(seed: Buffer, versions?: Versions): HDKeyT;
+  public static fromExtendedKey(base58key: string, versions?: Versions): HDKeyT;
   public static fromJSON(json: { xpriv: string }): HDKeyT;
 
   public versions: Versions;