update setup.py

Author: wenxuan0923

src/aks-preview/setup.py

@@ -9,7 +9,7 @@
 
 from setuptools import find_packages, setup
 
-VERSION = "18.0.0b28"
+VERSION = "18.0.0b29"
 
 CLASSIFIERS = [
     "Development Status :: 4 - Beta",