package/feh: update hash of license file

package/feh: update hash of license file

In commit 8d8caaf0c295e60fadc0dc14039376bfecb379fa ("package/feh: bump
version to 3.4.1"), feh was bumped from 3.4 to 3.4.1.

However, the hash of the license file was not updated, even though the
COPYING file had seen a copyright year update:

-Copyright (C) 2010-2018 Daniel Friesel.
+Copyright (C) 2010-2020 Daniel Friesel.

Let's update the license file hash to fix legal-info.

Fixes:

  http://autobuild.buildroot.net/results/991fb57bc99c2f44a00c846688f1b3e017b87724/

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>