fix: increase calendarbox width to show sundays (#437)

Author: tobifroe

djangocms_admin_style/sass/components/_forms.scss

@@ -667,7 +667,7 @@ div.calendar {
     }
 }
 div.calendarbox {
-    width: 230px !important;
+    width: 256px !important;
     table {
         margin-bottom: 0 !important;
         td {