build(pkgs/pistache): Use v${version} in revision so that nix-update can do its job

Author: PetarKirov

packages/pistache/default.nix

@@ -13,12 +13,12 @@
 }:
 stdenv.mkDerivation rec {
   pname = "pistache";
-  version = "2023-02-25";
+  version = "ver";
   src = fetchFromGitHub {
     owner = "pistacheio";
     repo = "pistache";
-    rev = "ae073a0709ed1d6f0c28db90766c64b06f0366e6";
-    hash = "sha256-4mqiQRL3ucXudNRvjCExPUAlz8Q5BzEqJUMVK6f30ug=";
+    rev = "${version}";
+    hash = "src-hash";
   };
 
   nativeBuildInputs = [