Update from debian/buster-security for apertis/v2021-security

Merge updates from Debian buster-security.

Also, in Apertis the build source stage performs a strict check of dependencies using dpkg-checkbuilddeps which fails due to the lack of libevent-dev.

Fix the issue by make the dependency explicit.

https://phabricator.apertis.org/T5378

Signed-off-by: Walter Lozano walter.lozano@collabora.com