Update history.yaml

Author: fungunga

_data/history.yaml

@@ -1,4 +1,10 @@
 ---
+- title: 'TextGrid Repository Maintenance'
+  date_start: '2024-06-20 15:30'
+  date_end: '2024-06-20 16:00'
+  description: 'Due to system migrations the repository services may not be available.'
+  affected:
+    - '/servers/textgrid-esx2'
 - title: 'DARIAH-DE/TextGrid Repository Maintenance'
   date_start: '2024-05-30 15:00'
   date_end: '2024-05-30 19:00'