Add changelog entry requirement to pull request template

Author: piotrmurach

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,18 +1,23 @@
 ### Describe the change
+
 What does this Pull Request do?
 
 ### Why are we doing this?
+
 Any related context as to why is this is a desirable change.
 
 ### Benefits
+
 How will the library improve?
 
 ### Drawbacks
+
 Possible drawbacks applying this change.
 
 ### Requirements
-Put an X between brackets on each line if you have done the item:
-[] Tests written & passing locally?
-[] Code style checked?
-[] Rebased with `master` branch?
-[] Documentation updated?
+<!--- Put an X between brackets on each line if you have done the item: -->
+- [ ] Tests written & passing locally?
+- [ ] Code style checked?
+- [ ] Rebased with `master` branch?
+- [ ] Documentation updated?
+- [ ] Changelog updated?