grep: Update to version 3.9

grep: Update to version 3.9

- Update from version 3.8 to 3.9
- Update of rootfile not required
- Changelog
 Noteworthy changes in release 3.9 (2023-03-05) [stable]
 Bug fixes
  With -P, some non-ASCII UTF8 characters were not recognized as
  word-constituent due to our omission of the PCRE2_UCP flag. E.g.,
  given f(){ echo Perú|LC_ALL=en_US.UTF-8 grep -Po "$1"; } and
  this command, echo $(f 'r\w'):$(f '.\b'), before it would print ":r".
  After the fix, it prints the correct results: "rú:ú".
  When given multiple patterns the last of which has a back-reference,
  grep no longer sometimes mistakenly matches lines in some cases.
  [Bug#36148#13 introduced in grep 3.4]

Signed-off-by: Adolf Belka <adolf.belka@ipfire.org>
Reviewed-by: Peter Müller <peter.mueller@ipfire.org>