deprecation of source_match(_re) and target_match(_re)

these settings have been deprecated since 2021

test is done by calling amtool in https://github.com/voxpupuli/puppet-prometheus/blob/master/spec/classes/alertmanager_spec.rb#L172

fixes #697

data/defaults.yaml

@@ -26,10 +26,10 @@ prometheus::alertmanager::global:
   'smtp_from': 'alertmanager@localhost'
 prometheus::alertmanager::group: 'alertmanager'
 prometheus::alertmanager::inhibit_rules:
-  - 'source_match':
-      'severity': 'critical'
-    'target_match':
-      'severity': 'warning'
+  - 'source_matchers':
+      - 'severity = critical'
+    'target_matchers':
+      - 'severity = warning'
     'equal':
       - 'alertname'
       - 'cluster'