gnused: 4.7 -> 4.8

Upstream announcement:
https://lists.gnu.org/archive/html/info-gnu/2020-01/msg00002.html



For the lazy:

> * Noteworthy changes in release 4.8 (2020-01-14) [stable]
>
> ** Bug fixes
>
>   "sed -i" now creates temporary files with correct umask (limited to u=rwx).
>   Previously sed would incorrectly set umask on temporary files, resulting
>   in problems under certain fuse-like file systems.
>   [bug introduced in sed 4.2.1]
>
> ** Release
>
>   distribute gzip-compressed tarballs once again
>
> ** Improvements
>
>   a year's worth of gnulib development, including improved DFA performance

Signed-off-by: Matthias Beyer <mail@beyermatthias.de>