fix(parcel): more robust handling of missing package.json

fixes #881

Author: trieloff

src/parcel/AdapterJSAsset.js

@@ -67,6 +67,11 @@ class AdapterJSAsset extends JSAsset {
       }
     }
   }
+
+  async getPackage() {
+    const pack = await super.getPackage();
+    return pack || {}; 
+  }
 }
 
 module.exports = AdapterJSAsset;