Update maintainer list

[skip ci]

libs/maintainers.txt

@@ -150,7 +150,7 @@ spirit/repository     Joel de Guzman <joel -at- boost-consulting.com>, Hartmut K
 stacktrace            Antony Polukhin <antoshkka -at- gmail.com>
 statechart            Andreas Huber <ahd6974-boostorg -at- yahoo.com>
 static_assert         John Maddock <john -at- johnmaddock.co.uk>
-static_string         Alan de Freitas <alandefreitas@gmail.com>, Vinnie Falco <vinnie.falco@gmail.com>
+static_string         Krystian Stasiowski <sdkrystian@gmail.com>, Alan de Freitas <alandefreitas@gmail.com>, Vinnie Falco <vinnie.falco@gmail.com>
 stl_interfaces        Zach Laine <whatwasthataddress -at- gmail.com>
 system                Peter Dimov <pdimov -at- gmail.com>
 test                  Gennadiy Rozental <rogeeff -at- gmail.com>, Raffi Enficiaud <raffi.enficiaud -at- free.fr>, Matt Borland <matt -at- mattborland.com>