MAINT: fix linter complaints

src/components/UserComponent.jsx

@@ -51,6 +51,13 @@ function _UserComponent({ session_info, logout_callback }) {
   );
 }
 
+_UserComponent.propTypes = {
+  session_info: PropTypes.shape({
+    username: PropTypes.string,
+  }),
+  logout_callback: PropTypes.func,
+}
+
 /**
  * @function onLogoutCallback
  *