add PR template file (#838)

* add PR template file

* Update .github/PULL_REQUEST_TEMPLATE.md

Co-authored-by: per1234 <[email protected]>

* Update .github/PULL_REQUEST_TEMPLATE.md

Co-authored-by: per1234 <[email protected]>

Co-authored-by: per1234 <[email protected]>

Author: fstasi

Diff for: .github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,15 @@
+### Motivation
+<!-- Why this pull request? -->
+
+### Change description
+<!-- What does your code do? -->
+
+### Other information
+<!-- Any additional information that could help the review process -->
+
+### Reviewer checklist
+
+* [ ] PR addresses a single concern.
+* [ ] The PR has no duplicates (please search among the [Pull Requests](https://github.com/arduino/arduino-ide/pulls) before creating one)
+* [ ] PR title and description are properly filled.
+* [ ] Docs have been added / updated (for bug fixes / features)