nix-shell: add milc dependency (#11086)

shell.nix

@@ -16,6 +16,25 @@ let
       inherit pname version;
       sha256 = "1yaimcgz8w0ps1wk28wk9g9zdidp79d14xqqj9rjkvxalvx2f5qx";
     };
+
+    doCheck = false;
+  };
+
+  milc = with pkgs.python3Packages; buildPythonPackage rec {
+    pname = "milc";
+    version = "1.0.10";
+
+    src = fetchPypi {
+      inherit pname version;
+      sha256 = "1q1p7qrqk78mw67nhv04zgxaq8himmdxmy2vp4fmi7chwgcbpi32";
+    };
+
+    propagatedBuildInputs = [
+      appdirs
+      argcomplete
+      colorama
+    ];
+
     doCheck = false;
   };
 
@@ -25,6 +44,7 @@ let
     argcomplete
     colorama
     hjson
+    milc
     pygments
     # requirements-dev.txt
     nose2