chore: update PR template (#4518)

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,11 +1,11 @@
 <!--
 *** Please remove the following help text before submitting: ***
 
+Provide a general summary of your changes in the Title above
+
 Pull requests without a rationale and clear improvement may be closed
 immediately.
--->
 
-<!--
 Please provide clear motivation for your patch and explain how it improves
 Dash Core user experience or Dash Core developer experience
 significantly:
@@ -22,3 +22,32 @@ significantly:
   If a feature is based on a lot of dependencies, contributors should first
   consider building the system outside of Dash Core, if possible.
 -->
+
+## Issue being fixed or feature implemented
+<!--- Why is this change required? What problem does it solve? -->
+<!--- If it fixes an open issue, please link to the issue here. -->
+
+
+## What was done?
+<!--- Describe your changes in detail -->
+
+
+## How Has This Been Tested?
+<!--- Please describe in detail how you tested your changes. -->
+<!--- Include details of your testing environment, and the tests you ran to -->
+<!--- see how your change affects other areas of the code, etc. -->
+
+
+## Breaking Changes
+<!--- Please describe any breaking changes your code introduces -->
+
+
+## Checklist:
+<!--- Go over all the following points, and put an `x` in all the boxes that apply. -->
+- [ ] I have performed a self-review of my own code
+- [ ] I have commented my code, particularly in hard-to-understand areas
+- [ ] I have added or updated relevant unit/integration/functional/e2e tests
+- [ ] I have made corresponding changes to the documentation
+
+**For repository code-owners and collaborators only**
+- [ ] I have assigned this pull request to a milestone