[ci] explicitly add needed packages for nix release target

nix/pkgs.nix

@@ -23,6 +23,13 @@ let
         then value.overrideScope' ocamlOverlay
         else value
     ) super.ocaml-ng;
+    release = self.callPackage ./release.nix {
+      git = pkgs.git;
+      jq = pkgs.jq;
+      curl = pkgs.curl;
+      git-lfs = pkgs.git-lfs;
+      opam = pkgs.opam;
+    };
   };
   with_overlay = pkgs.appendOverlays [ overlay ];
 in

nix/release.nix

+{
+  stdenv,
+  curl,
+  git,
+  git-lfs,
+  jq,
+  opam
+}:
+stdenv.mkDerivation rec {
+  name = "release";
+  buildInputs = [
+    curl
+    git
+    git-lfs
+    jq
+    opam
+  ];
+}