maintainers: add anpin

maintainers/maintainer-list.nix

···
     githubId = 1342360;
     name = "Andrew Morgan";
   };
+  anpin = {
+    email = "[e-mail]";
+    github = "anpin";
+    githubId = 6060545;
+    matrix = "@anpin:matrix.org";
+    name = "Pavel Anpin";
+    keys = [{
+      fingerprint = "06E8 4FF6 0CCF 7AFD 5101  76C9 0FBC D3EE 6310 7407";
+    }];
+  };
   anpryl = {
     email = "[e-mail]";
     github = "anpryl";