fix nix-autoupgrade email notification to use system msmtp config

platforms/nixos/modules/nmasur/presets/programs/msmtp/msmtp.nix

@@ -47,6 +47,7 @@ in
           host = cfg.host;
           passwordeval = "${pkgs.age}/bin/age --decrypt --identity ${config.identityFile} ${pkgs.writeText "mailpass-system.age" (builtins.readFile cfg.passwordFile)}";
           user = cfg.user;
+          from = cfg.user;
           from_full_name = "${config.networking.hostName} System";
           port = 465;
           tls = true;

platforms/nixos/modules/nmasur/presets/services/nix-autoupgrade.nix

@@ -6,7 +6,6 @@
 }:
 
 let
-  inherit (config.nmasur.settings) username;
   cfg = config.nmasur.presets.services.nix-autoupgrade;
 in
 
@@ -27,7 +26,7 @@ in
     system.autoUpgrade = {
       enable = true;
       dates = "09:33";
-      flake = "git+${cfg.repo}";
+      flake = "git+ssh://${cfg.repo}";
       randomizedDelaySec = "25min";
       operation = "switch";
       allowReboot = true;
@@ -55,8 +54,7 @@ in
           systemctl status $SERVICE_ID >> $TEMPFILE
           set -e
           ${lib.getExe pkgs.msmtp} \
-              --file=${config.home-manager.users.${username}.xdg.configHome}/msmtp/config \
-              --account=system \
+              --account=default \
               ${address} < $TEMPFILE
         '';
       };