libdigidoc: add myself as maintainer

I'd like to get notifications for bumps of this, considering it's used
in qdigidoc, a package I maintain.

pkgs/by-name/li/libdigidocpp/package.nix

@@ -72,6 +72,9 @@ stdenv.mkDerivation rec {
     homepage = "https://www.id.ee/";
     license = licenses.lgpl21Plus;
     platforms = platforms.linux;
-    maintainers = [ maintainers.jagajaga ];
+    maintainers = [
+      maintainers.flokli
+      maintainers.jagajaga
+    ];
   };
 }