gcc48, gfortran48: add myself as maintainer

cc #61130

(cherry picked from commit bf1818dd5dd80724ece212850b7686feb7021a42)

pkgs/development/compilers/gcc/4.8/default.nix

···
       compiler used in the GNU system including the GNU/Linux variant.
     '';
 
-    maintainers = with stdenv.lib.maintainers; [ peti ];
+    maintainers = with stdenv.lib.maintainers; [ peti veprbl ];
 
     platforms =
       stdenv.lib.platforms.linux ++