chore: add pull request template (#176)

* add pull request template

* fix: use safe related issue placeholder in PR template

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Co-authored-by: kongenpei <kongenpei@users.noreply.github.com>

.github/pull_request_template.md

@@ -0,0 +1,16 @@
+## Summary
+<!-- Briefly describe the motivation and scope of this change in 1-3 sentences. -->
+
+## Changes
+<!-- List the main changes in this PR. -->
+- Change 1
+- Change 2
+
+## Test Plan
+<!-- Describe how this change was verified. -->
+- [ ] Unit tests pass
+- [ ] Manual local verification confirms the `lark xxx` command works as expected
+
+## Related Issues
+<!-- Link related issues. Use Closes/Fixes to close them automatically. -->
+- None