(maint) Fix centos spec tests

Prior to this commit, the centos spec tests were not matching into with
the os name fact and being skipped. This commit fixes those spec tests
by adding Centos to the when case.

Author: Jarret Lavallee

spec/classes/repos_spec.rb

@@ -25,7 +25,7 @@ class {'puppet_metrics_dashboard':
         # rubocop:disable RSpec/RepeatedDescription
         # rubocop:disable RSpec/RepeatedExample
         case facts[:os]['name']
-        when 'RedHat'
+        when 'RedHat', 'CentOS'
           it 'should contain the yum repo for InfluxDB' do
             is_expected.to contain_yumrepo('influxdb')
               .with(