{AzureMonitor} fixes Azure#22716 fix the Metrics API version in the package-composite-v1 tag (Azure#22792)

fixes Azure#22716 

fix the Metrics API version in the package-composite-v1 tag

Author: navba-MSFT

specification/monitor/resource-manager/readme.md

@@ -145,7 +145,7 @@ input-file:
 - Microsoft.Insights/stable/2015-04-01/eventCategories_API.json
 - Microsoft.Insights/stable/2015-04-01/tenantActivityLogs_API.json
 - Microsoft.Insights/stable/2018-01-01/metricDefinitions_API.json
-- Microsoft.Insights/stable/2018-01-01/metrics_API.json
+- Microsoft.Insights/stable/2021-05-01/metrics_API.json
 - Microsoft.Insights/stable/2019-03-01/metricBaselines_API.json
 - Microsoft.Insights/stable/2018-03-01/metricAlert_API.json
 - Microsoft.Insights/stable/2022-06-15/scheduledQueryRule_API.json