Add pull request template

Author: janbarasek

.github/pull_request_template.md

@@ -0,0 +1,10 @@
+- bug fix / new feature?   <!-- #issue numbers, if any -->
+- BC break? yes/no
+
+<!--
+Describe your changes here to communicate to the maintainers why we should accept this pull request.
+
+Please add new tests to show the fix or feature works.
+
+Thanks for contributing to Baraja opensource ecosystem!
+-->