maintainers: add tejing

maintainers/maintainer-list.nix

···
     github = "tejasag";
     githubId = 67542663;
   };
+  tejing = {
+    name = "Jeff Huffman";
+    email = "[e-mail]";
+    matrix = "@tejing:matrix.org";
+    github = "tejing1";
+    githubId = 5663576;
+    keys = [{ fingerprint = "6F0F D43B 80E5 583E 60FC  51DC 4936 D067 EB12 AB32"; }];
+  };
   telotortium = {
     email = "[e-mail]";
     github = "telotortium";