Added WaitSeconds info

It is helpful for long-running Account Specific issues.

shd-notifier/README.md

@@ -50,11 +50,16 @@ The CloudFormation template requires the following parameters:
   - 0 (Disable Debugging)
   - 1 (Enable debugging)
 
+- **WaitSeconds** - Control State Machine wait period of state transition. Allowed values:
+  - 60 (1 minutes - Allows Standard State machine to run for 2.5 days)
+  - 300 (5 minutes - Allows Standard State machine to run for 12.5 days)
+  - 600 (10 minutes - Allows Standard State machine to run for 25 days)
+
 #### Post-CloudFormation Installation Step
 Due to the CloudFormation limit on inline Lambda functions, after the CloudFormation stack has completed successfully, the **deploy.sh** script will need to be run to update the code for the Lambda functions. <br />
 Syntax: **deploy.sh** _\<CF_APPNAME\>_ _\<REGION\>_ <br/>
   - *CF_APPNAME* = The *AppName* defined when deploying the CloudFormation template
   - *REGION* = The region of the deployed CloudFormation template 
 
 ### License
-AWS Health Tools are licensed under the Apache 2.0 License.
+AWS Health Tools are licensed under the Apache 2.0 License.