Add changelog and documentation to PR chore list (#2346)

The PR proposes to extend the PR chore list with changelog and
documentation notes.

Author: antonwolfy

.github/pull_request_template.md

@@ -1,6 +1,7 @@
 - [ ] Have you provided a meaningful PR description?
-- [ ] Have you added a test, reproducer or referred to issue with a reproducer?
+- [ ] Have you added a test, reproducer or referred to an issue with a reproducer?
 - [ ] Have you tested your changes locally for CPU and GPU devices?
 - [ ] Have you made sure that new changes do not introduce compiler warnings?
 - [ ] Have you checked performance impact of proposed changes?
-- [ ] If this PR is a work in progress, are you filing the PR as a draft?
+- [ ] Have you added documentation for your changes, if necessary?
+- [ ] Have you added your changes to the changelog?