updated copyright year

[Pádraig Brady]

https://git.sv.gnu.org/gitweb/?p=coreutils.git;a=commitdiff;h=ff2f852
Author: Pádraig Brady <address@hidden>
Date:   Wed Jan 1 14:36:12 2020 +0000

    maint: adjust to split out xstrtol-error gnulib module

    * bootstrap.conf: Depend on the new module split from xstrtol.
    * src/df.c: Include "xstrtol-error.h" for xstrtol_fatal.
    * src/du.c: Likewise.
    * src/ls.c: Likewise.
    * src/od.c: Likewise.
    * src/pr.c: Likewise.
    * src/sort.c: Likewise.

https://git.sv.gnu.org/gitweb/?p=coreutils.git;a=commitdiff;h=aaba824
Author: Pádraig Brady <address@hidden>
Date:   Wed Jan 1 14:16:56 2020 +0000

    maint: update all copyright year number ranges

    Run "make update-copyright" and then...

    * gnulib: Update to latest with copyright year adjusted.
    * tests/init.sh: Sync with gnulib to pick up copyright year.
    * bootstrap: Likewise.
    * tests/sample-test: Adjust to use the single most recent year.