fix(manifest:serialize): don't include npmpkg wrapping type

src/manifest/npm/mod.rs

@@ -6,6 +6,7 @@ pub use self::commonjs::CommonJSPackage;
 pub use self::esmodules::ESModulesPackage;
 
 #[derive(Serialize)]
+#[serde(untagged)]
 pub enum NpmPackage {
     CommonJSPackage(CommonJSPackage),
     ESModulesPackage(ESModulesPackage),