dissect+peek: avoid deprecated ndn-cxx functions

Change-Id: Ibd9f8ad30e315f537d1560db823372af3d58d713
diff --git a/tools/dump/ndndump.hpp b/tools/dump/ndndump.hpp
index 9d786e7..83b0710 100644
--- a/tools/dump/ndndump.hpp
+++ b/tools/dump/ndndump.hpp
@@ -105,7 +105,7 @@
   std::string interface;
   std::string inputFile;
   std::string pcapFilter{getDefaultPcapFilter()};
-  optional<std::regex> nameFilter;
+  std::optional<std::regex> nameFilter;
   bool wantPromisc = true;
   bool wantTimestamp = true;
   bool wantVerbose = false;