chore: improve nix-ci:build build time by using only builtins.toJSON

removes dependency on remarshal, pkgs.formats.json uses jq to pretty
print so we just use builtins.toJSON directly

lib/flakeModule.nix

@@ -161,7 +161,15 @@
       };
 
       config.legacyPackages = let
-        toYaml = (pkgs.formats.yaml {}).generate;
+        # NOTE: json is also valid yaml and this removes dependency on jq
+        #  and/or remarshal (used in pkgs.formats.json and pkgs.formats.yaml
+        #  respectively)
+        toYaml = name: value:
+          pkgs.runCommand name {} ''
+            cat <<EOT >> $out
+            ${builtins.toJSON value}
+            EOT
+          '';
         mapAttrs = cb: set: builtins.listToAttrs (builtins.map (key: cb key (builtins.getAttr key set)) (builtins.attrNames set));
         prepend = key: arr: job:
           job