RtNotificationsTest.java:47-49: Create a test...

The puzzle `920-4390f200` from #920 has to be resolved:

https://github.com/jcabi/jcabi-github/blob/36b7b8e022c257ded6cd67b8a7cface4c5ec77f8/src/test/java/com/jcabi/github/RtNotificationsTest.java#L47-L49

The puzzle was created by Yegor Bugayenko on 05-Jul-22.

role: DEV.

If you have any technical questions, don't ask me, submit new tickets instead. The task will be \"done\" when the problem is fixed and the text of the puzzle is _removed_ from the source code. Here is more about [PDD](http://www.yegor256.com/2009/03/04/pdd.html) and [about me](http://www.yegor256.com/2017/04/05/pdd-in-action.html).