update default config of inplace (#864)

* update quant docs

* Update quantization_api.rst

* Update quantization_api.rst

* Update quantization_api.rst

* Update qat.py

与之前版本兼容：之前版本直接改动传入的model，所以这里inplace改为true

paddleslim/dygraph/quant/qat.py

@@ -207,7 +207,7 @@ class QAT(object):
             weight_quantize_layer=self.weight_quantize,
             act_quantize_layer=self.act_quantize)
 
-    def quantize(self, model, inplace=False):
+    def quantize(self, model, inplace=True):
         """
         Quantize the input model.