"this x" is not recognized

[cakebaker]

GNU date recognizes "this x", for example:

$ date --date="this year"
Tue Jun 20 10:50:27 AM CEST 2023
$ date --date="this week"
Tue Jun 20 10:50:51 AM CEST 2023

uutils date, using parse_datetime, doesn't recognize "this x" and returns an "invalid date" error instead.