Update readme for multi pubsub (#437)

* update readme for multi pubsub

* move paragraph up

* typo

Co-authored-by: LM <lemai>

README.md

@@ -277,20 +277,19 @@ $ dapr run --app-id nodeapp --app-port 3000 node app.js
 
 Publish a message:
 
-```
-$ dapr publish --topic myevent
-```
+The `--pubsub` parameter takes in the name of the pub/sub.  The default name of the pub/sub configed by the CLI is "pubsub".
+
 
 Publish a message:
 
 * Linux/Mac
 ```bash
-$ dapr publish --topic myevent --data '{ "name": "yoda" }'
+$ dapr publish --pubsub pubsub --topic myevent --data '{ "name": "yoda" }'
 ```
 
 * Windows
 ```bash
-C:> dapr publish --topic myevent --data "{ \"name\": \"yoda\" }"
+C:> dapr publish --pubsub pubsub --topic myevent --data "{ \"name\": \"yoda\" }"
 ```
 
 ### Invoking