.github: add a template for pull requests requesting testing info

Author: peterbarker

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,10 @@
+## Description
+
+<!-- Describe your changes here -->
+
+## Testing (your PR may be summarily closed without these)
+
+- [ ] Tested in SITL, logs attached
+- [ ] Tested on hardware, logs attached or available on request
+- [ ] Autotest included
+- [ ] Not AI slop