tests: Set Apertis version to v2300

In the unlikely cases tests scripts run against a production
instance (which they never should), this may prevent a catastrophe.

Signed-off-by: Andrej Shadura <andrew.shadura@collabora.co.uk>

tests/backend-config/BSConfig.local.pm

 my @reprepro_releases = ("v2022");
-my @aptly_releases = ("v2023");
+my @aptly_releases = ("v2300");
 my @apertis_components = ("target", "development", "sdk");
 my $apertis_prefix = "shared/apertis/public/apertis";
 my $aptly_server = {