Specify "token" argument name in example code block in README.md. (slackapi#420)

Max McBride · Mark Preston · commit 45c1930cc9fa · 2019-05-15T22:03:12.000+01:00
Otherwise there seems to be a consistent exception being thrown:
&gt; TypeError: __init__() takes 1 positional argument but 2 were given
diff --git a/README.md b/README.md
@@ -143,7 +143,7 @@ In our example below, we watch for a [message event][message-event] that contain
             )
 
     slack_token = os.environ["SLACK_API_TOKEN"]
-    rtm_client = slack.RTMClient(slack_token)
+    rtm_client = slack.RTMClient(token=slack_token)
     rtm_client.start()
 ```
 

Original file line number	Diff line number	Diff line change
`@@ -143,7 +143,7 @@ In our example below, we watch for a [message event][message-event] that contain`
`143`	`143`	`)`
`144`	`144`
`145`	`145`	`slack_token = os.environ["SLACK_API_TOKEN"]`
`146`		`- rtm_client = slack.RTMClient(slack_token)`
	`146`	`+ rtm_client = slack.RTMClient(token=slack_token)`
`147`	`147`	`rtm_client.start()`
`148`	`148`	```
`149`	`149`