chore: Add PR template checkbox for cross sdk review on public API changes (#6386)

Add PR template checkbox for cross sdk review on public API changes

Co-authored-by: LucasZF <lucas-zimerman1@hotmail.com>

Author: antonis

.github/pull_request_template.md

@@ -20,11 +20,12 @@
 
 ## :pencil: Checklist
 <!--- Put an `x` in the boxes that apply -->
-- [ ] I added tests to verify changes
-- [ ] No new PII added or SDK only sends newly added PII if `sendDefaultPII` is enabled
+- [ ] I added tests to verify changes.
+- [ ] No new PII added or SDK only sends newly added PII if `sendDefaultPII` is enabled.
 - [ ] I updated the docs if needed.
 - [ ] I updated the wizard if needed.
-- [ ] All tests passing
-- [ ] No breaking changes
+- [ ] All tests passing.
+- [ ] Public API changes reviewed by another Mobile SDK team member or implemented according to the [develop docs](https://develop.sentry.dev/) spec.
+- [ ] No breaking changes.
 
 ## :crystal_ball: Next steps