Update from debian/buster for apertis/v2021dev3

debian/changelog

+base-files (10.3+deb10u4co1) UNRELEASED; urgency=medium
+
+  * PLEASE SUMMARIZE remaining Apertis changes
+
+ -- root <ritesh.sarraf@collabora.co.uk>  Wed, 01 Jul 2020 15:19:12 +0000
+
+base-files (10.3+deb10u4) buster; urgency=medium
+
+  * Change /etc/debian_version to 10.4, for Debian 10.4 point release.
+
+ -- Santiago Vila <sanvila@debian.org>  Sat, 02 May 2020 18:39:00 +0200
+
 base-files (10.3+deb10u3co5) apertis; urgency=medium
 
   * Bump version numbers to v2021dev2.