This commit updates the week-numbering year format from `r` -> `Y` based on the description in
http://www.unicode.org/reports/tr35/tr35-dates.html#dfst-year.
Note: this is not a breaking change, since the week-numbering year format was introduced in
v11.0.0-next.3 (984ed39195)
and the major version that contains that change was not released yet.
PR Close#39495