Update maintainer list

[skip ci]

libs/maintainers.txt

@@ -116,7 +116,7 @@ preprocessor          Paul Mensonides <pmenso57 -at- comcast.net>, Edward Diener
 process               Klemens D. Morgenstern <klemens.morgenstern -at- gmx.net>
 program_options       Vladimir Prus <vladimir.prus -at- gmail.com>
 property_map          Douglas Gregor <dgregor -at- cs.indiana.edu>
-property_tree         Sebastian Redl <sebastian.redl -at- getdesigned.at>
+property_tree         Richard Hodges <hodges.r@gmail.com>
 proto                 Eric Niebler <eric -at- boostpro.com>
 ptr_container         Thorsten Ottosen <nesotto -at- cs.auc.dk>
 python                Stefan Seefeld <stefan -at- seefeld.name>