Fix typo from 'orderWidth' to 'borderWidth' (react-navigation#1438)

Co-authored-by: Satyajit Sahoo <satyajit.happy@gmail.com>

Author: yash2974

versioned_docs/version-7.x/drawer-navigator.md

@@ -329,7 +329,7 @@ Example:
    drawerItemStyle: {
     backgroundColor: '#9dd3c8',
     borderColor: 'black',
-    orderWidth: 2,
+    borderWidth: 2,
     opacity: 0.6,
   },
 ```

versioned_docs/version-8.x/drawer-navigator.md

@@ -329,7 +329,7 @@ Example:
    drawerItemStyle: {
     backgroundColor: '#9dd3c8',
     borderColor: 'black',
-    orderWidth: 2,
+    borderWidth: 2,
     opacity: 0.6,
   },
 ```