Revert "Upgrade ocm.software/ocm-gear/prometheus"

This reverts commit 6a0607e.

Author: 8R0WNI3

.ocm/base-component.yaml

@@ -7,7 +7,7 @@ componentReferences:
   version: 0.1206.0
 - componentName: ocm.software/ocm-gear/delivery-database
   name: delivery-database
-  version: 0.16.0
+  version: 0.15.0
 - componentName: ocm.software/ocm-gear/prometheus
   name: prometheus
   version: 0.15.0