adding pull request template

pull_request_template.md

@@ -0,0 +1,17 @@
+## Description of Changes
+
+Please clearly state what you have changed and why you made these changes.
+
+## Testing Done
+
+Please describe the tests that you ran to verify your changes.
+
+## Related Issue(s)
+
+Please link the related issues.
+
+---
+
+By submitting this pull request, I confirm that my contribution is made under the terms of the [Contributor License Agreement (CLA)](https://github.com/mgear-dev/mgear4/blob/master/Contributor_License_Agreement.md). Please use the CLA assistant to sign the CLA
+
+