frudevice: include filesystem header explicitly

Signed-off-by: Patrick Venture <venture@google.com>
Change-Id: Idd943dd7da5559e2ab94181070e1797f89b1bca3
diff --git a/src/FruDevice.cpp b/src/FruDevice.cpp
index 72c2a95..fd45775 100644
--- a/src/FruDevice.cpp
+++ b/src/FruDevice.cpp
@@ -24,6 +24,7 @@
 #include <boost/container/flat_map.hpp>
 #include <chrono>
 #include <ctime>
+#include <filesystem>
 #include <fstream>
 #include <future>
 #include <iostream>