added shadow effect to button

components/button.component.js

@@ -17,7 +17,11 @@ const styles = StyleSheet.create({
     fontSize: 16,
     backgroundColor: themeColors.PRIMARY_COLOR,
     borderRadius: 20,
-    margin: 20
+    shadowColor: 'rgba(0,0,0, .4)',
+    shadowOffset: { height: 2, width: 1 },
+    shadowOpacity: 1,
+    shadowRadius: 1,
+    elevation: 2,
   },
   label: {
     fontFamily: 'Poppins-Black',