Updated pmmetrics package to support for VOL-1091 and VOL-1381, This is to collect PMMetics for OLT.
Updated with SendKPIevent2 method
Updated with review comments

Change-Id: Ib2461f1fa6003a74372737c08e3bc2305667f2ce
diff --git a/pkg/adapters/adapterif/core_proxy_if.go b/pkg/adapters/adapterif/core_proxy_if.go
index 196f356..615452c 100644
--- a/pkg/adapters/adapterif/core_proxy_if.go
+++ b/pkg/adapters/adapterif/core_proxy_if.go
@@ -37,6 +37,7 @@
 	DeviceStateUpdate(ctx context.Context, deviceID string,
 		connStatus voltha.ConnectStatus_ConnectStatus, operStatus voltha.OperStatus_OperStatus) error
 
+	DevicePMConfigUpdate(ctx context.Context, pmConfigs *voltha.PmConfigs) error
 	ChildDeviceDetected(ctx context.Context, parentDeviceID string, parentPortNo int,
 		childDeviceType string, channelID int, vendorID string, serialNumber string, onuID int64) (*voltha.Device, error)