Upload android-pl.py

Add "metadata" to android-pl.py

android-pl.py

@@ -28,6 +28,7 @@ class Android(datasets.GeneratorBasedBuilder):
                 "_id": datasets.Value("string"), 
                 "title": datasets.Value("string"),
                 "text": datasets.Value("string"),
+                "metadata": dict()
              }),
             supervised_keys=None,
         )