Add back PR template.

Author: yo1995

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,27 @@
+## Description
+
+This PR implements `SAMPLE_NAME` in `SAMPLE_CATEGORY` category.
+URL to README: 
+
+## Linked Issue(s)
+
+- `swift/issues/`
+
+## How To Test
+
+
+## Screenshots
+
+|Before|After|
+|:-:|:-:|
+|||
+
+## To Discuss
+
+<details><summary>Code Snippet</summary>
+
+```swift
+Swift repro code goes here
+```
+
+</details>