Add Pull Request Template

Author: ShinryakuTako

.github/pull_request_template.md

@@ -0,0 +1,18 @@
+---
+name: Pull request
+about: An awesome contribution
+
+---
+
+- Category: 'API/Functionality/Component/Language/Style/other'
+- Target Platform: 'iOS/macOS/tvOS/Universal'
+- Any other info?
+ 
+**Is your pull request related to an issue?**
+A link to the issue.
+
+**Describe the solution offered by your pull request**
+A clear description of your commit(s).
+
+**Additional context**
+Add any other context or screenshots etc. related to your pull request here.