maintainers: add Sébastien Guimmara

Author: sguimmara

maintainers/maintainer-list.nix

@@ -21496,6 +21496,12 @@
     githubId = 1151264;
     name = "Sebastian Graf";
   };
+  sguimmara = {
+    email = "[email protected]";
+    github = "sguimmara";
+    githubId = 5512096;
+    name = "Sébastien Guimmara";
+  };
   shackra = {
     name = "Jorge Javier Araya Navarro";
     email = "[email protected]";