chore: updating the PR template (#32546)

### Description of changes

Update the PR template to ask contributor to list the changes to any IAM or Resource policies.

### Checklist
- [X] My code adheres to the [CONTRIBUTING GUIDE](https://github.com/aws/aws-cdk/blob/main/CONTRIBUTING.md) and [DESIGN GUIDELINES](https://github.com/aws/aws-cdk/blob/main/docs/DESIGN_GUIDELINES.md)

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*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

Author: moelasmar

.github/PULL_REQUEST_TEMPLATE.md

@@ -8,7 +8,16 @@ Closes #<issue number here>.
 
 ### Description of changes
 
-<!--What code changes did you make? Have you made any important design decisions?-->
+<!--
+What code changes did you make? 
+Have you made any important design decisions?
+What AWS use cases does this change enable? To enable the use cases, which AWS service features are utilized?
+-->
+
+### Describe any new or updated permissions being added
+
+<!— What new or updated IAM permissions are needed to support the changes being introduced ? -->
+
 
 ### Description of how you validated changes