chore: Added Pull Request Template

Author: MarcusNotheis

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,8 @@
+**Thank you for your contribution!** 👏
+
+To get it merged faster, kindly review the checklist below:
+
+## Pull Request Checklist
+- [ ] Reviewed the [Contributing Guidelines](https://github.com/SAP/fiori-for-react/blob/master/CONTRIBUTING.md)
+    + Especially the [How to Contribute](https://github.com/SAP/fiori-for-react/blob/master/CONTRIBUTING.md#contribute-code) section 
+- [ ] [Correct commit message style](https://github.com/SAP/fiori-for-react/blob/master/docs/Guidelines.md#commit-message-style)