Merge pull request #347 from rstudio/update-pull-request-template

Update pull_request_template.md

Author: tdstein

.github/pull_request_template.md

@@ -29,7 +29,5 @@
 ## Checklist:
 <!--- Go over all the following points, and put an `x` in all the boxes that apply: -->
 <!--- If you need clarification on any of these, feel free to ask. We're here to help! -->
-- [ ] I have read the **CONTRIBUTING** document.
-- [ ] My code follows the code style of this project.
-- [ ] I have updated the documentation as needed.
-- [ ] I have added tests to cover my changes.
+- [ ] I have added tests to cover my changes.
+- [ ] I have updated [CHANGELOG.md](../CHANGELOG.md) to cover notable changes.