Fix typo in example code in readme

Author: jordan-brough

README.md

@@ -369,7 +369,7 @@ stepFunctions:
 Disables output in the CloudFormation Outputs section.  if you define many state-machines in serverless.yml, there is a possibility of reaching out a CloudFormation limits in which the maximum number of outputs is 60. If you define `noOutput: true`, you can prevent automatically output by this plugin.
 
 ```yaml
-stepFUnctions:
+stepFunctions:
   noOutput: true
 ```