feat(route): Add GitHub Notification (#12197)

* Add GitHub notification

* add docs and radar.

* add parseDate.

* Apply suggestions from code review

* Update router.js

* Update maintainer.js

---------

lib/v2/github/radar.js

@@ -80,6 +80,12 @@ module.exports = {
                 source: ['/:user/:repo/wiki/:page/_history', '/:user/:repo/wiki/:page', '/:user/:repo/wiki/_history', '/:user/:repo/wiki'],
                 target: '/github/wiki/:user/:repo/:page',
             },
+            {
+                title: 'Notifications 通知',
+                docs: 'https://docs.rsshub.app/programming.html#github',
+                source: ['/notifications'],
+                target: '/github/notifications',
+            },
         ],
     },
 };