[VOL-5222] - Upgrade golang version for VOLTHA jobs

.gitreview
VERSION
----------
  o post-release tasks.  Repository tagged and banched.
  o Add missing newlines at EOF.
  o go.mod syntax does not allow *-dev suffix so update
    master VERSION from v5.5.0-dev to v5.5.0.  Community
    can introduce a dev version when needed.

go/*.pb.og
vendor/*.go
-----------
  o invoke make mod-update to regenerate go.sum and friends.
  o lint clenaups: find . -name '*.go' -print | xargs -n1 gofmt -s -e -w

Change-Id: I3da80c0ce5600679b388e309bfa4702f1ec3212b
diff --git a/vendor/google.golang.org/grpc/attributes/attributes.go b/vendor/google.golang.org/grpc/attributes/attributes.go
index ae13dda..02f5dc5 100644
--- a/vendor/google.golang.org/grpc/attributes/attributes.go
+++ b/vendor/google.golang.org/grpc/attributes/attributes.go
@@ -19,7 +19,7 @@
 // Package attributes defines a generic key/value store used in various gRPC
 // components.
 //
-// Experimental
+// # Experimental
 //
 // Notice: This package is EXPERIMENTAL and may be changed or removed in a
 // later release.