Fix e-mail regex. Apostrophes are allowed in local parts but we use them to deliminate strings in the sieve script.

This directive is supposed to prevent mail delivery loops that would be caused by portforwarding to itself.
Behind this ip address, however, there is our general mail vm and not immediately the mailinglist setup.

flake.nix

@@ -19,6 +19,7 @@
       inputs = {
         flake-compat.follows = "";
         gitignore.follows = "";
+        nixpkgs-stable.follows = "";
         nixpkgs.follows = "";
       };
     };

nixos/machines/nodens/hardware-configuration.nix

@@ -30,28 +30,16 @@
   fileSystems."/mnt/persist" = {
     device = "/dev/disk/by-label/nixos";
     fsType = "btrfs";
-    options = [
-      "subvol=persist"
-      "users" # Allows any user to mount and unmount
-      "nofail" # Prevent system from failing if this drive doesn't mount
-    ];
+    options = ["subvol=persist"];
   };
   fileSystems."/mnt/boot" = {
     device = "/dev/disk/by-label/boot";
     fsType = "ext4";
-    options = [
-      "users" # Allows any user to mount and unmount
-      "nofail" # Prevent system from failing if this drive doesn't mount
-    ];
   };
   fileSystems."/mnt/nix" = {
     device = "/dev/disk/by-label/nixos";
     fsType = "btrfs";
-    options = [
-      "subvol=nix"
-      "users" # Allows any user to mount and unmount
-      "nofail" # Prevent system from failing if this drive doesn't mount
-    ];
+    options = ["subvol=nix"];
   };
 
   swapDevices = [{device = "/dev/disk/by-uuid/89e13a83-506a-43b4-b06a-09424500ceda";}];