use filesystem instead of experimental

Use filesystem now that it should be available instead of
experimental::filesystem.

Change-Id: I62838b343ce34f85a47661f1eaaff3c7e6338bbf
Signed-off-by: Patrick Venture <venture@google.com>
diff --git a/sensorset.cpp b/sensorset.cpp
index f326e88..e3f4e9c 100644
--- a/sensorset.cpp
+++ b/sensorset.cpp
@@ -17,7 +17,7 @@
 
 #include "hwmon.hpp"
 
-#include <experimental/filesystem>
+#include <filesystem>
 #include <iostream>
 #include <regex>
 
@@ -29,7 +29,7 @@
 
 SensorSet::SensorSet(const std::string& path)
 {
-    namespace fs = std::experimental::filesystem;
+    namespace fs = std::filesystem;
 
     for (const auto& file : fs::directory_iterator(path))
     {