Return all day off recorded for given month.
GET
/data/persons/day-offs/{year}/{month}
curl \
--request GET http://api.example.com/data/persons/day-offs/{year}/{month} \
--header "Authorization: $API_KEY"
curl \
--request GET http://api.example.com/data/persons/day-offs/{year}/{month} \
--header "Authorization: $API_KEY"