fix for pgl for the erniesage

fix for pgl for the erniesage

PaddleNLP/examples/text_graph/erniesage/config/erniesage_link_prediction.yaml

 # Global Enviroment Settings 
 
 # trainer config ------
-n_gpu: 2 # delete it, if use cpu to train
+n_gpu: 1 # number of gpus used to train, delete it, if use cpu
 seed: 2020
 
 task: "link_prediction"

PaddleNLP/examples/text_graph/erniesage/data/dataset.py

@@ -21,7 +21,7 @@ from paddle.io import Dataset, IterableDataset
 from paddlenlp.utils.log import logger
 import pgl
 from pgl import Graph
-from pgl.nn.sampling import graphsage_sample
+from pgl.sampling import graphsage_sample
 
 __all__ = [
     "TrainData",