add PR template

.github/pull_request_template.md

@@ -0,0 +1,29 @@
+<!--
+# Have you read capa's CONTRIBUTING guide?
+It contains helpful information about how to contribute to capa. Check https://github.com/fireeye/capa/blob/master/.github/CONTRIBUTING.md
+
+based on https://embeddedartistry.com/blog/2017/08/04/a-github-pull-request-template-for-your-projects/
+-->
+
+### Description
+
+closes # (issue)
+
+<!-- Description of the PR -->
+
+### Type of change
+
+- [ ] Bug fix (non-breaking change which fixes an issue)
+- [ ] New feature (non-breaking change which adds functionality)
+- [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
+- [ ] This change requires a documentation update
+
+### Tests
+
+- [ ] I have added tests that prove my fix is effective or that my feature works
+- [ ] No new tests needed
+
+### Checklist
+
+- [ ] I have updated the [CHANGELOG.md](/CHANGELOG.md)
+- [ ] I have made corresponding changes to the documentation