add `platforms.all`

pkgs/tools/package-management/micromamba/default.nix

@@ -63,6 +63,7 @@ stdenv.mkDerivation rec {
     description = "Reimplementation of the conda package manager";
     homepage = "https://github.com/mamba-org/mamba";
     license = licenses.bsd3;
+    platforms = platforms.all;
     maintainers = with maintainers; [ mausch ];
   };
 }