chore(governance): refresh pull request template sections

Author: heitorlessa

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,25 +1,40 @@
-**Issue #, if available:**
+**Issue number:**
 
-## Description of changes:
+## Summary
 
-<!--- One or two sentences as a summary of what's being changed -->
+### Changes
 
-**Checklist**
+> Please provide a summary of what's being changed
 
-<!--- Leave unchecked if your change doesn't seem to apply --> 
+### User experience
+
+> Please share what the user experience looks like before and after this change
+
+## Checklist
+
+If your change doesn't seem to apply, please leave them unchecked.
 
 * [ ] [Meet tenets criteria](https://awslabs.github.io/aws-lambda-powertools-python/#tenets)
-* [ ] Update tests
-* [ ] Update docs
+* [ ] I have performed a self-review of my this change
+* [ ] Changes are tested
+* [ ] Changes are documented
 * [ ] PR title follows [conventional commit semantics](https://github.com/awslabs/aws-lambda-powertools-python/blob/376ec0a2ac0d2a40e0af5717bef42ff84ca0d1b9/.github/semantic.yml#L2)
 
-## Breaking change checklist
 
-<!--- Ignore if it's not a breaking change -->
+<details>
+<summary>Is this a breaking change?</summary>
+
+**RFC issue number**:
 
-**RFC issue #**:
+Checklist:
 
 * [ ] Migration process documented
 * [ ] Implement warnings (if it can live side by side)
 
+</details>
+
+## Acknowledgment
+
 By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.
+
+**Disclaimer**: We value your time and bandwidth. As such, any pull requests created on non-triaged issues might not be successful.