docs: replace outdated deployment parameter (#5361)

docs: remove outdated API

Author: Sherlock113

docs/source/scale-with-bentocloud/deployment/manage-deployments.rst

@@ -241,7 +241,7 @@ To roll out a Deployment:
       bentoml.deployment.update(name="deployment-1", bento="bento_name:version")
 
       # Use the project directory
-      bentoml.deployment.update(name="deployment-1", project_path="./project/directory")
+      bentoml.deployment.update(name="deployment-1", bento="./project/directory")
 
 Apply
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