Update google-ads version to 15.0.0 (#580)

Author: laurachevalier4

setup.py

@@ -34,7 +34,7 @@
 
 setup(
     name="google-ads",
-    version="14.1.0",
+    version="15.0.0",
     author="Google LLC",
     author_email="googleapis-packages@google.com",
     classifiers=[