Update pull_request_template.md (#590)

Signed-off-by: Matt Ramotar <mramotar@dropbox.com>

pull_request_template.md

@@ -1,3 +1,25 @@
-Please see our contributing guidelines (contributing.md) primarily make sure to sign our cla as we cannot accept code externally without a signed cla
+Closes # (Issue number)
 
-https://opensource.dropbox.com/cla/
+## Description
+What changes are you introducing with this PR? Please include motivation and context.
+
+## 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
+
+## Test Plan
+How has this been tested? Please describe the tests that you added to verify your changes.
+
+## Checklist:
+Before submitting your PR, please review and check all of the following:
+- [ ] I have performed a self-review of my own code
+- [ ] I have commented my code, particularly in hard-to-understand areas
+- [ ] I have made corresponding changes to the documentation
+- [ ] My changes generate no new warnings
+- [ ] I have added tests that prove my change is effective
+- [ ] New and existing unit tests pass locally with my changes
+
+## Additional Notes:
+Add any other information about the PR here.