Use shorter dayIncrement

aleksis/apps/chronos/frontend/components/substitutions/SubstitutionOverview.vue

@@ -29,6 +29,7 @@ import { DateTime } from "luxon";
     :enable-edit="true"
     :elevated="false"
     :force-model-item-update="true"
+    :dayIncrement="3"
     empty-icon="mdi-account-multiple-check-outline"
     ref="iterator"
   >