maintainers: add samuel-martineau

maintainers/maintainer-list.nix

···
     githubId = 132835;
     name = "Samuel Dionne-Riel";
   };
+  samuel-martineau = {
+    name = "Samuel Martineau";
+    email = "[e-mail]";
+    github = "Samuel-Martineau";
+    githubId = 44237969;
+    keys = [{
+      fingerprint = "79A1 CC17 67C7 32B6 A8A2  BF4F 71E0 8761 642D ACD2";
+    }];
+  };
   samuelrivas = {
     email = "[e-mail]";
     github = "samuelrivas";