chore: improve the PR template (#1051)

Signed-off-by: behnazh-w <[email protected]>

Author: behnazh-w

.github/pull_request_template.md

@@ -1,12 +1,18 @@
-## Checklist
-<!-- Go over following points. check them with an `x` if they do apply, (they turn into clickable checkboxes once the PR is submitted, so no need to do everything at once)
+## Summary
+<!-- Briefly summarize the purpose and scope of this PR. -->
+
+## Description of changes
+<!-- Provide a detailed explanation of the changes made in this PR, why they were needed, and how they address the issue(s). -->
 
--->
+## Related issues
+<!-- List any related issue(s) this PR addresses, e.g., `Closes #123`, `Fixes #456`. -->
+
+## Checklist
+<!-- Go over following points. check them with an `x` if they do apply, (they turn into clickable checkboxes once the PR is submitted, so no need to do everything at once) -->
 
 - [ ] I have reviewed the [contribution guide](../CONTRIBUTING.md).
 - [ ] My PR title and commits follow the [Conventional Commits](https://www.conventionalcommits.org/en/v1.0.0/) convention.
 - [ ] My commits include the "Signed-off-by" line.
 - [ ] I have signed my commits following the instructions provided by [GitHub](https://docs.github.com/en/authentication/managing-commit-signature-verification/signing-commits). Note that we run [GitHub's commit verification](https://docs.github.com/en/authentication/managing-commit-signature-verification/about-commit-signature-verification) tool to check the commit signatures. A green `verified` label should appear next to **all** of your commits on GitHub.
 - [ ] I have updated the relevant documentation, if applicable.
 - [ ] I have tested my changes and verified they work as expected.
-- [ ] I have referenced the issue(s) this pull request solves.