Merge branch 'add-registration-link' into 'master'

Add registration link for 2020-07-23 Python workshop

See merge request hifis/hifis.net!278

_events/2021/07/2021-07-23-python.md

@@ -10,7 +10,7 @@ start:
     date:   "2021-07-23"
 end:
     date:   "2021-07-23"
-registration_link:
+registration_link: "https://events.hifis.net/event/160/"
 location:
     campus: Online
 fully_booked_out: false