minor rc fix (#373)

Author: Shrestha Malik

python/setup.in.py

@@ -59,7 +59,7 @@ def get_tag(self):
 
 setup( 
     name='ngraph_tensorflow_bridge',
-    version='0.21.0rc2',
+    version='0.21.0rc1',
     description='Intel nGraph compiler and runtime for TensorFlow',
     long_description=long_description,
     long_description_content_type="text/markdown",