[VOL-3860] redis client support in voltha-lib-go

redis client support has been added in this patch. There are two
types client `redis` and `redis-sentinel` to connect a redis instance.
redis-sentinel is required to be able to find the master redis
instance from a redis-sentinel process. See redis-sentinel usage
https://redis.io/topics/sentinel and
https://pkg.go.dev/github.com/go-redis/redis/v8#NewFailoverClient
for more information. If there is no need to have any failover
mechanism then the redis client type is the option to choose.

Change-Id: I997ed92115a9d565df632c6dd8184b9bab77b991
diff --git a/vendor/go.opentelemetry.io/otel/api/metric/doc.go b/vendor/go.opentelemetry.io/otel/api/metric/doc.go
new file mode 100644
index 0000000..48a59c5
--- /dev/null
+++ b/vendor/go.opentelemetry.io/otel/api/metric/doc.go
@@ -0,0 +1,50 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package metric provides support for reporting measurements using instruments.
+//
+// Instruments are categorized as below:
+//
+// Synchronous instruments are called by the user with a Context.
+// Asynchronous instruments are called by the SDK during collection.
+//
+// Additive instruments are semantically intended for capturing a sum.
+// Non-additive instruments are intended for capturing a distribution.
+//
+// Additive instruments may be monotonic, in which case they are
+// non-descreasing and naturally define a rate.
+//
+// The synchronous instrument names are:
+//
+//   Counter:           additive, monotonic
+//   UpDownCounter:     additive
+//   ValueRecorder:     non-additive
+//
+// and the asynchronous instruments are:
+//
+//   SumObserver:       additive, monotonic
+//   UpDownSumObserver: additive
+//   ValueObserver:     non-additive
+//
+// All instruments are provided with support for either float64 or
+// int64 input values.
+//
+// The Meter interface supports allocating new instruments as well as
+// interfaces for recording batches of synchronous measurements or
+// asynchronous observations.  To obtain a Meter, use a MeterProvider.
+//
+// The MeterProvider interface supports obtaining a named Meter interface. To
+// obtain a MeterProvider implementation, initialize and configure any
+// compatible SDK.
+package metric // import "go.opentelemetry.io/otel/api/metric"