add support for arm64 Debian repos

manifests/repo.pp

@@ -118,6 +118,9 @@
 
         if ($facts['os']['distro']['id'] == 'Raspbian') {
           $operatingsystem = 'raspbian'
+        } elsif ($facts['os']['architecture'] in ['arm64', 'aarch64']) {
+          # arm64 is the Debian name, but some facter versions report aarch64 instead
+          $operatingsystem = "${downcase($facts['os']['name'])}-arm64"
         } else {
           $operatingsystem = downcase($facts['os']['name'])
         }

spec/classes/repo_spec.rb

@@ -1,5 +1,6 @@
 # frozen_string_literal: true
 
+require 'deep_merge'
 require 'spec_helper'
 
 describe 'zabbix::repo' do
@@ -45,6 +46,16 @@
             it { is_expected.to contain_apt__source('zabbix').with_location('http://repo.zabbix.com/zabbix/5.0/debian/') }
           end
         end
+
+        %w[arm64 aarch64].each do |arch|
+          context "on #{arch}" do
+            let :facts do
+              facts.deep_merge(os: { architecture: arch })
+            end
+
+            it { is_expected.to contain_apt__source('zabbix').with_location("http://repo.zabbix.com/zabbix/6.0/#{facts[:os]['name'].downcase}-arm64/") }
+          end
+        end
       when 'RedHat'
 
         it { is_expected.to compile.with_all_deps }