clang-tidy: use using

Found with modernize-use-using

Signed-off-by: Rosen Penev <rosenp@gmail.com>

src/futils.cpp

@@ -362,7 +362,7 @@ namespace Exiv2 {
     {
         Uri result;
 
-        typedef std::string::const_iterator iterator_t;
+        using iterator_t = std::string::const_iterator;
 
         if ( !uri.length() )  return result;