Fix: issue 128 Replace defaultProps with JavaScript default paramet…

…ers for functional components

This PR addresses the deprecation warning related to the use of defaultProps in functional components, as seen in the warning message pointed in issue# 128:

Warning: y: Support for defaultProps will be removed from function components in a future major release. Use JavaScript default parameters instead.

src/index.js

@@ -252,9 +252,9 @@ StepWizard.defaultProps = {
 };
 
 export const Step = ({
-    children,
-    isActive,
-    transitions,
+    children = [],
+    isActive = false,
+    transitions = '',
 }) => (
     <div className={`${styles.step} ${transitions} ${isActive ? styles.active : ''}`.trim()}>
         { children }
@@ -268,9 +268,3 @@ if (process.env.NODE_ENV !== 'production') {
         transitions: PropTypes.string,
     };
 }
-
-Step.defaultProps = {
-    children: [],
-    isActive: false,
-    transitions: '',
-};