squashfsTools: update package metadata

I am adding myself as maintainer here for lack of a better candidate,
but I am not experienced with Nix, and I am not a squashfs expert
either.

maintainers/maintainer-list.nix

@@ -3234,6 +3234,11 @@
     github = "rushmorem";
     name = "Rushmore Mushambi";
   };
+  ruuda = {
+    email = "dev+nix@veniogames.com";
+    github = "ruuda";
+    name = "Ruud van Asseldonk";
+  };
   rvl = {
     email = "dev+nix@rodney.id.au";
     github = "rvl";

pkgs/tools/filesystems/squashfs/default.nix

@@ -38,5 +38,7 @@ stdenv.mkDerivation rec {
     homepage = http://squashfs.sourceforge.net/;
     description = "Tool for creating and unpacking squashfs filesystems";
     platforms = stdenv.lib.platforms.linux;
+    license = stdenv.lib.licenses.gpl2Plus;
+    maintainers = with stdenv.lib.maintainers; [ ruuda ];
   };
 }