Add an example of iterating through pull request changed files in ruby.

I currently got this much done on it myself, however with not knowing ruby much at all I am not sure if I coded it all right. The code lies at https://github.com/Elskom/CI/blob/master/CI.rb. Yes it is formatted like the building a CI server example but with pull request label check for "skip news", and a "Misc/NEWS" entry check for if a new file was added there. I am not sure how I can filter it though to where that check only works with new entry files, not modified or deleted ones unless all of them merged to a single file (like right before a release). I would also love to be able to have my CI read comments from repo /org admins though for things like "I approve this" where the CI then approves the changes and then waits for "merge squashed/rebased/commit". I personally think it would be great to have an example like that tbh. And yes, feel free to use the code I got so far on an example, I don’t mind if you guys even linked to it too. Also I thought those octocat stuff was some sort of photoshopped thing. 🤔

Beginne mit der Durchsicht von CI.rb und des bestehenden Beispiels zum Erstellen eines CI-Servers. Ermittle, wie das Beispiel die geänderten Dateien eines Pull Requests untersuchen, neu hinzugefügte Misc/NEWS-Einträge von geänderten oder gelöschten Dateien unterscheiden und den angeforderten Workflow für Labels und Administrator-Kommentare handhaben sollte. Als abgeschlossen gilt die Aufgabe, wenn das Ruby-Beispiel die vereinbarten Prüfungen sowie das Genehmigungs- oder Merge-Verhalten klar demonstriert.

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