FileSequenceFunctions : Add include required by Boost 1.85

Author: murraystevenson

src/IECore/FileSequenceFunctions.cpp

@@ -43,6 +43,7 @@
 
 #include "boost/algorithm/string.hpp"
 #include "boost/filesystem/convenience.hpp"
+#include "boost/filesystem/directory.hpp"
 #include "boost/filesystem/operations.hpp"
 #include "boost/filesystem/path.hpp"
 #include "boost/format.hpp"