Add PR template

Author: erichlf

.github/pull_request_template.md

@@ -0,0 +1,36 @@
+Description of MR/PR...
+
+Fixes #
+
+[comment]: # (To refer to GitHub issues in other repos)
+
+## Motivation and Context
+
+Why is this change implemented? Add screenshots, images, or other media if this helps explain.
+
+## Changes
+
+- Item 1
+- Item 2
+
+## Type of changes
+
+- Bug fix (non-breaking change which fixes an issue)
+- New feature (non-breaking change which adds functionality)
+- Breaking change (fix or feature that would cause existing functionality to change)
+
+[comment]: # (Delete the lines in "Type of changes" that are not appropriate)
+
+## Checklist
+
+- [ ] Update dependencies
+- [ ] Update version
+- [ ] Update README
+
+## Testing
+
+This should contain instructions on how to test the new code, or details on how
+the new code was tested, e.g.
+
+1. `colcon build --symlink-install --merge-install --packages-up-to py_trees_parser`
+2. `colcon test --merge-install --event-handlers console_cohesion+ --packages-select py_trees_parser`