refactor(directory): add eslint

directory/src/component/main_border.jsx

@@ -1,3 +1,5 @@
+import React from 'react';
+import PropTypes from 'prop-types';
 import './main_border.css';
 
 export default function MainBorder(props) {
@@ -6,4 +8,7 @@ export default function MainBorder(props) {
       {props.children}
     </section>
   )
-}
+}
+MainBorder.propTypes = {
+  children: PropTypes.node,
+};