Fix rollout schedule landing a week late [skip-ci]

Next Tuesday'/'Next Monday' resolve to the following calendar week when the script is run on a Monday. Bare weekday names schedule the upcoming occurrence instead.

TYPE: Bugfix
LINK: None

Author: Tschuppi81

maintenance-schedule.yml

@@ -1,23 +1,23 @@
 schedule:
-  - date: Next Tuesday at 12:00
+  - date: Tuesday at 12:00
     nodes:
       - loxo
       - pherusa
       - tyche
-  - date: Next Tuesday at 14:00
+  - date: Tuesday at 14:00
     nodes:
       - aether
       - alecto
       - theros
       - arete
       - calais
-  - date: Next Tuesday at 15:00
+  - date: Tuesday at 15:00
     nodes:
       - caicias
       - caicinus
       - caicus
       - carcinus
-  - date: Next Monday +7 days at 7:00
+  - date: Monday +7 days at 7:00
     nodes:
       - ister
       - istrus