Adding a new pull request template

Author: BooleanCube

.github/PULL_REQUEST_TEMPLATE/pull_request_template.md

@@ -0,0 +1,9 @@
+## Describe your changes
+
+## Issue ticket number and link
+
+## Checklist before requesting a review
+- [ ] I have performed a self-review of my code and passed all written tests in the `tests/` directory.
+- [ ] If it is a core feature, I have added thorough tests.
+- [ ] Do we need to implement analytics?
+- [ ] Will this be part of a product update? If yes, please write one phrase about this update.