Update PULL_REQUEST_TEMPLATE.md (#624)

Author: PatrickBue

.github/PULL_REQUEST_TEMPLATE.md

@@ -11,7 +11,8 @@
 <!--- Go over all the following points, and put an `x` in all the boxes that apply. -->
 <!--- If you're unsure about any of these, don't hesitate to ask. We're here to help! -->
 - [ ] I have followed the [contribution guidelines](../CONTRIBUTING.md) and code style for this project.
+- [ ] This branch is created from `staging` and not `master`.
+- [ ] This PR is being made to `staging` and not `master`.
+- [ ] I will squash merge this PR into `staging`.
 - [ ] I have added tests covering my contributions.
 - [ ] I have updated the documentation accordingly.
-- [ ] This PR is being made to `staging` and not `master`
-- [ ] I will squash merge this PR into `staging`