Returns a copy of this {@code LocalDate} with the specified period in years added.
This method adds the specified amount to the years field in three steps:
- Add the input years to the year field
- Check if the resulting date would be invalid
- Adjust the day-of-month to the last valid day if necessary
For example, 2008-02-29 (leap year) plus one year would result in the invalid date 2009-02-29 (standard year). Instead of returning an invalid result, the last valid day of the month, 2009-02-28, is selected instead.
This instance is immutable and unaffected by this method call.
@param yearsToAdd the years to add, may be negative
@return a {@code LocalDate} based on this date with the years added, not null
@throws DateTimeException if the result exceeds the supported date range