grep: upgrade 3.10 -> 3.11

This is to announce grep-3.11, a stable release.

This release makes PCRE patterns like [\d] work again, at the expense of
reverting to the behavior of grep 3.8, in that patterns like \w and \b go
back to using ASCII rather than Unicode interpretations.  However, if you
build grep using pcre2 newer than 10.42, then \w and \b do work properly.

Signed-off-by: Denys Dmytriyenko <denis@denix.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>