Add missing postgresql-client package for backup gem

roles/postgresql_primary.rb

@@ -5,4 +5,5 @@ run_list %w(
   kosmos_postgresql::firewall
   kosmos_gitea::pg_db
   kosmos_drone::pg_db
+  kosmos-mastodon::pg_db
 )

site-cookbooks/backup/metadata.rb

@@ -8,3 +8,4 @@ name "backup"
 
 depends 'logrotate'
 depends 'mysql'
+depends 'postgresql'

site-cookbooks/backup/recipes/default.rb

@@ -3,6 +3,7 @@
 # Recipe:: default
 #
 
+apt_package 'postgresql-client-12'
 build_essential 'backup gem'
 
 # Don't try to install packages on older Ubuntu, the repositories are 404