Set default git branch name

default branch name is now "main" instead of "master"

modules/shell/git.nix

@@ -22,6 +22,7 @@
         gpg.format = "ssh";
         gpg.ssh.allowedSignersFile = "~/.ssh/allowed_signers";
         user.signingkey = "~/.ssh/git.pub";
+        init.defaultBranch = "main";
       };
     };
   };