[auto]: add PR template

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,8 @@
+# Checklist
+<!-- Put an `x` in each box when you have completed the items. -->
+- [ ] App update process has been followed <!-- See comment below -->
+- [ ] Target branch is `develop` <!-- unless you have a very good reason -->
+- [ ] Application version has been bumped <!-- required if your changes are to be deployed -->
+
+<!-- Make sure you followed the process described in https://developers.ledger.com/docs/embedded-app/maintenance/ before opening your Pull Request.
+Don't hesitate to contact us directly on Discord if you have any questions ! https://developers.ledger.com/discord -->