[Doc] [Serve] Fix typo in serve dev workflow (ray-project#34713)

Change the --working_dir command line option to --working-dir.

Closes ray-project#34691

doc/source/serve/dev-workflow.md

@@ -88,7 +88,7 @@ When making the transition from your local machine to a remote cluster, you'll n
 Let's see a simple example that just packages the code. Run the following command on your local machine, with your remote cluster head node IP address substituted for `<head-node-ip-address>` in the command:
 
 ```bash
-serve run --address=ray:https://<head-node-ip-address>:10001 --working_dir="./project/src" local_dev:graph
+serve run --address=ray:https://<head-node-ip-address>:10001 --working-dir="./project/src" local_dev:graph
 ```
 
 This will connect to the remote cluster via Ray Client, upload the `working_dir` directory, and run your serve application. Here, the local directory specified by `working_dir` must contain `local_dev.py` so that it can be uploaded to the cluster and imported by Ray Serve.