Cherry-pick #18005 to 7.x: Disable repository expiration checks in Journalbeat builds

[jsoriano]

Cherry-pick of PR #18005 to 7.x branch. Original message:

Journalbeat builds are failing in all branches with errors like the following one:

W: GPG error: http://archive.debian.org jessie Release: The following signatures were invalid: KEYEXPIRED 1587841717
WARNING: The following packages cannot be authenticated!
  liblzma5:i386 libgpg-error0:i386
E: There are problems and -y was used without --force-yes
Error: running "apt-get install -y --no-install-recommends -o Acquire::Check-Valid-Until=false libsystemd-dev:i386 libsystemd0:i386 libgcrypt20:i386" failed with exit code 100

Jessie repositories are not updated anymore and their keys got outdated a couple of days ago.

# apt-key list | grep expired
pub   4096R/46925553 2012-04-27 [expired: 2020-04-25]
pub   4096R/65FFB764 2012-05-08 [expired: 2019-05-07]

I tried to disable only expiration checks with -o Acquire::Check-Valid-Until=false but it was not enough.

I am disabling all authentication checks for packages installation during Journalbeat builds. We should review this in a follow up, so we don't build with unauthenticated packages.

[mikemadden42]

run beats-ci/package

[mikemadden42]

LGTM