!14650 fix broken package metadata content

From: @nicholas_yhr
Reviewed-by: @jjfeing,@kisnwang,@zhoufeng54
Signed-off-by: @lilongfei15

setup.py

@@ -196,7 +196,7 @@ setup(
     },
     description='MindSpore is a new open source deep learning training/inference '
     'framework that could be used for mobile, edge and cloud scenarios.',
-    long_description="\n\n".join(readme),
+    long_description=readme,
     long_description_content_type="text/markdown",
     packages=find_packages(),
     package_data=package_data,