[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/modules.txt b/vendor/modules.txt
index 27153e7..1c6a0e2 100644
--- a/vendor/modules.txt
+++ b/vendor/modules.txt
@@ -107,6 +107,8 @@
 # github.com/dgrijalva/jwt-go v3.2.0+incompatible
 ## explicit
 github.com/dgrijalva/jwt-go
+# github.com/dgryski/go-rendezvous v0.0.0-20200823014737-9f7001d12a5f
+github.com/dgryski/go-rendezvous
 # github.com/dustin/go-humanize v1.0.0
 ## explicit
 github.com/dustin/go-humanize
@@ -117,6 +119,15 @@
 github.com/eapache/go-xerial-snappy
 # github.com/eapache/queue v1.1.0
 github.com/eapache/queue
+# github.com/go-redis/redis/v8 v8.3.4
+## explicit
+github.com/go-redis/redis/v8
+github.com/go-redis/redis/v8/internal
+github.com/go-redis/redis/v8/internal/hashtag
+github.com/go-redis/redis/v8/internal/pool
+github.com/go-redis/redis/v8/internal/proto
+github.com/go-redis/redis/v8/internal/rand
+github.com/go-redis/redis/v8/internal/util
 # github.com/gogo/protobuf v1.3.2
 github.com/gogo/protobuf/gogoproto
 github.com/gogo/protobuf/proto
@@ -327,6 +338,19 @@
 go.etcd.io/etcd/clientv3
 go.etcd.io/etcd/embed
 go.etcd.io/etcd/etcdserver/api/v3rpc/rpctypes
+# go.opentelemetry.io/otel v0.13.0
+go.opentelemetry.io/otel
+go.opentelemetry.io/otel/api/global
+go.opentelemetry.io/otel/api/global/internal
+go.opentelemetry.io/otel/api/metric
+go.opentelemetry.io/otel/api/metric/registry
+go.opentelemetry.io/otel/api/trace
+go.opentelemetry.io/otel/codes
+go.opentelemetry.io/otel/internal
+go.opentelemetry.io/otel/internal/baggage
+go.opentelemetry.io/otel/internal/trace/noop
+go.opentelemetry.io/otel/label
+go.opentelemetry.io/otel/unit
 # go.uber.org/atomic v1.7.0
 go.uber.org/atomic
 # go.uber.org/multierr v1.6.0