Update batman-adv to 2023.2

pkgs/os-specific/linux/batman-adv/version.nix

···
   version = "2023.1";
 
   sha256 = {
-    batman-adv = "sha256-9GpyhmYKXsNQahvn72C0ccUaxwVQWX1ZgEBHmre5Nrg=";
-    alfred = "sha256-Q4BIJI83N1fTqL3ny8bbZoX00BBdEw2i9aVPKQkMaXQ=";
-    batctl = "sha256-5b9HMF2VWrsZkkS9Dl//q5YQixr/q9DZcFUz+AWTlfE=";
+    batman-adv = lib.fakeSha256;
+    alfred = lib.fakeSha256;
+    batctl = lib.fakeSha256;
   };
 }