nodePackages.parsoid: pin service-runner to 2.3.0

service-runner had a backwards incompatible update, and parsoid 0.9.0
doesn't work with current stable MediaWiki. Instead use as a source
a repository with 0.8.0 and pinned service-runner version.

nixos/modules/services/misc/parsoid.nix

@@ -6,6 +6,8 @@ let
 
   cfg = config.services.parsoid;
 
+  parsoid = pkgs.nodePackages."parsoid-git://github.com/abbradar/parsoid#stable";
+
   confTree = {
     worker_heartbeat_timeout = 300000;
     logging = { level = "info"; };
@@ -93,7 +95,7 @@ in
       after = [ "network.target" ];
       serviceConfig = {
         User = "nobody";
-        ExecStart = "${pkgs.nodePackages.parsoid}/lib/node_modules/parsoid/bin/server.js -c ${confFile} -n ${toString cfg.workers}";
+        ExecStart = "${parsoid}/lib/node_modules/parsoid/bin/server.js -c ${confFile} -n ${toString cfg.workers}";
       };
     };