[build] Update python-wheel target path to latest in master (sonic-net#253)

Author: prgeor

azure-pipelines.yml

@@ -54,7 +54,7 @@ steps:
     sudo pip3 install sonic_yang_mgmt-1.0-py3-none-any.whl
     sudo pip3 install sonic_yang_models-1.0-py3-none-any.whl
     sudo pip3 install sonic_config_engine-1.0-py3-none-any.whl
-  workingDirectory: $(Pipeline.Workspace)/target/python-wheels/
+  workingDirectory: $(Pipeline.Workspace)/target/python-wheels/buster/
   displayName: 'Install Python dependencies'
 
 - script: |