Chore: add prerequisites checklist to PR template (#12790)

* Chore: add prerequisites checklist to PR template

* Add friendly message at top

* Address feedback

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,8 +1,15 @@
 <!--
+    Thank you for contributing!
+
     ESLint adheres to the [JS Foundation Code of Conduct](https://js.foundation/community/code-of-conduct).
 -->
 
-**What is the purpose of this pull request? (put an "X" next to item)**
+#### Prerequisites checklist
+
+- [ ] I have read the [contributing guidelines](https://github.com/eslint/eslint/blob/master/CONTRIBUTING.md).
+- [ ] The team has reached consensus on the changes proposed in this pull request. If not, I understand that the evaluation process will begin with this pull request and won't be merged until the team has reached consensus.
+
+#### What is the purpose of this pull request? (put an "X" next to item)
 
 [ ] Documentation update
 [ ] Bug fix ([template](https://raw.githubusercontent.com/eslint/eslint/master/templates/bug-report.md))
@@ -29,9 +36,7 @@
     The following is required for all pull requests:
 -->
 
-**What changes did you make? (Give an overview)**
-
-
-**Is there anything you'd like reviewers to focus on?**
+#### What changes did you make? (Give an overview)
 
 
+#### Is there anything you'd like reviewers to focus on?