Rename Prometheus to OpenMetrics (#10973)
Rename Prometheus to OpenMetrics (#10973)

Changes incorrect instance of Prometheus to OpenMetrics
DataDog/integrations-core,DataDog/integrations-core,DataDog/integrations-core,DataDog/integrations-core,DataDog/integrations-core,DataDog/integrations-core,DataDog/integrations-core,DataDog/integrations-core,DataDog/integrations-core,DataDog/integrations-core