Add memgraph namespace

tests/unit/network_utils.cpp

@@ -1,4 +1,4 @@
-// Copyright 2021 Memgraph Ltd.
+// Copyright 2022 Memgraph Ltd.
 //
 // Use of this software is governed by the Business Source License
 // included in the file licenses/BSL.txt; by using this file, you agree to be bound by the terms of the Business Source
@@ -14,7 +14,7 @@
 
 #include "io/network/utils.hpp"
 
-using namespace io::network;
+using namespace memgraph::io::network;
 
 TEST(ResolveHostname, Simple) {
   auto result = ResolveHostname("localhost");