misc: add pr template (sgl-project#309)

Author: JamesBrianD

.github/pull_request_template.md

@@ -0,0 +1,24 @@
+<!-- Thank you for your contribution! Please follow these guidelines to enhance your pull request. If anything is unclear, submit your PR and reach out to maintainers for assistance. -->
+
+## Motivation
+
+<!-- Describe the purpose and goals of this pull request. -->
+
+## Modifications
+
+<!-- Detail the changes made in this pull request. -->
+
+## Accuracy Tests
+
+<!-- If this pull request affects model outputs (e.g., changes to the kernel or model forward code), provide accuracy test results. -->
+
+## Benchmarking and Profiling
+
+<!-- If this pull request impacts inference speed, provide benchmarking and profiling results. -->
+
+## Checklist
+
+- [ ] Please use English, otherwise it will be closed.
+- [ ] The purpose of the PR, or link existing issues this PR will resolve.
+- [ ] The test plan, such as providing test command.
+- [ ] (Optional) The necessary documentation update.