maintainers: remove martingms

I'm currently not using neither mypy nor nixpkgs, so can't be of much
help.

maintainers/maintainer-list.nix

@@ -11745,12 +11745,6 @@
     githubId = 1729331;
     name = "Dominique Martinet";
   };
-  martingms = {
-    email = "martin@mg.am";
-    github = "martingms";
-    githubId = 458783;
-    name = "Martin Gammelsæter";
-  };
   martinjlowm = {
     email = "martin@martinjlowm.dk";
     github = "martinjlowm";

pkgs/development/python-modules/mypy/default.nix

@@ -118,6 +118,6 @@ buildPythonPackage rec {
     homepage = "https://www.mypy-lang.org";
     license = licenses.mit;
     mainProgram = "mypy";
-    maintainers = with maintainers; [ martingms lnl7 ];
+    maintainers = with maintainers; [ lnl7 ];
   };
 }

pkgs/development/python-modules/mypy/extensions.nix

@@ -42,6 +42,6 @@ buildPythonPackage rec {
     description = "Experimental type system extensions for programs checked with the mypy typechecker";
     homepage = "https://www.mypy-lang.org";
     license = licenses.mit;
-    maintainers = with maintainers; [ martingms lnl7 ];
+    maintainers = with maintainers; [ lnl7 ];
   };
 }