Upgrade Babel to v7

[MAILPOET-1683]

assets/js/src/common/key_value_table.jsx

@@ -29,4 +29,4 @@ KeyValueTable.defaultProps = {
   max_width: 'auto',
 };
 
-module.exports = KeyValueTable;
+export default KeyValueTable;

assets/js/src/common/print_boolean.jsx

@@ -24,4 +24,4 @@ PrintBoolean.defaultProps = {
   children: null,
 };
 
-module.exports = PrintBoolean;
+export default PrintBoolean;

assets/js/src/common/stepped_progess_bar.jsx

@@ -25,4 +25,4 @@ SteppedProgressBar.propTypes = {
   step: PropTypes.number.isRequired,
 };
 
-module.exports = SteppedProgressBar;
+export default SteppedProgressBar;