maintainers: add pho

maintainers/maintainer-list.nix

···
     githubId = 421510;
     name = "Noé Rubinstein";
   };
+  pho = {
+    email = "[e-mail]";
+    github = "pho";
+    githubId = 88469;
+    name = "Jaime Breva";
+  };
   photex = {
     email = "[e-mail]";
     github = "photex";