maintainer-list.nix: replace vikanezrimaya's github username

I updated my github username for consistency over all of the online
services I use.

maintainers/maintainer-list.nix

···
     githubId = 5837359;
     name = "Adrian Pistol";
   };
-  vika_nezrimaya = {
+  vikanezrimaya = {
     email = "[e-mail]";
-    github = "kisik21";
+    github = "vikanezrimaya";
     githubId = 7953163;
     name = "Vika Shleina";
     keys = [{

pkgs/tools/system/lr/default.nix

···
     description = "List files recursively";
     license = licenses.mit;
     platforms = platforms.all;
-    maintainers = with maintainers; [ vika_nezrimaya ];
+    maintainers = with maintainers; [ vikanezrimaya ];
   };
 }