mopidy-spotify: add myself as maintainer

It's a simple enough package, I do use it and it's unmaintained,
I might as well volunteer for it.

maintainers/maintainer-list.nix

@@ -12316,4 +12316,10 @@
     github = "zupo";
     githubId = 311580;
   };
+  rski = {
+    name = "rski";
+    email = "rom.skiad+nix@gmail.com";
+    github = "rski";
+    githubId = 2960312;
+  };
 }

pkgs/applications/audio/mopidy/spotify.nix

@@ -19,7 +19,7 @@ pythonPackages.buildPythonApplication rec {
     homepage = "https://www.mopidy.com/";
     description = "Mopidy extension for playing music from Spotify";
     license = licenses.asl20;
-    maintainers = [];
-    hydraPlatforms = [];
+    maintainers = with maintainers; [ rski ];
+    hydraPlatforms = [ ];
   };
 }