Adding pull request template for flytekit (#91)

- Copying over pull_request_template.
 - Currently there is no boilerplate in the code

pull_request_template.md

@@ -0,0 +1,26 @@
+# TL;DR
+_Please replace this text with a description of what this PR accomplishes._
+
+## Type
+ - [ ] Bug Fix
+ - [ ] Feature
+ - [ ] Plugin
+
+## Are all requirements met?
+
+ - [ ] Code completed
+ - [ ] Smoke tested
+ - [ ] Unit tests added
+ - [ ] Code documentation added
+ - [ ] Any pending items have an associated Issue
+
+## Complete description
+ _How did you fix the bug, make the feature etc. Link to any design docs etc_
+
+## Tracking Issue
+https://github.com/lyft/flyte/issues/<number>
+
+## Follow-up issue
+_NA_
+OR
+_https://github.com/lyft/flyte/issues/<number>_