!15197 update the version from 1.2.0-rc1 to 1.2.0

From: @luopengting
Reviewed-by: @majorzhang,@lilongfei15,@xsmq
Signed-off-by: @lilongfei15

setup.py

@@ -23,7 +23,7 @@ from setuptools import setup, find_packages
 from setuptools.command.egg_info import egg_info
 from setuptools.command.build_py import build_py
 
-version = '1.2.0-rc1'
+version = '1.2.0'
 
 backend_policy = os.getenv('BACKEND_POLICY')
 device_target = os.getenv('BACKEND_TARGET')