ENH: Support for "52–53-week fiscal year" / "4–4–5 calendar" and LastWeekOfMonth DateOffset.
- Added ``LastWeekOfMonth`` DateOffset
- Added ``FY5253LastOfMonthQuarter``, ``FY5253LastOfMonth``, ``FY5253NearestEndMonth``, and ``FY5253NearestEndMonthQuarter`` DateOffsets