[doc] added pull request template (#2550)

* [doc] added pull  request template

* polish code

* polish code

.github/pull_request_template.md

+## 📌 Checklist before creating the PR
+
+- [ ] I have created an issue for this PR for traceability
+- [ ] The title follows the standard format: `[doc/gemini/tensor/...]: A concise description`
+- [ ] I have added relevant tags if possible for us to better distinguish differnt PRs
+
+
+## 🚨 Issue number
+
+> Link this PR to your issue with words like fixed to automatically close the linked issue upon merge
+>
+> e.g. fixed #1234, closed #1234, resolved #1234
+
+
+
+## 📝 What does this PR do?
+
+> Summarize your work here.
+> if you have any plots/diagrams/screenshots/tables, please attach them here.
+
+
+
+## 💥 Checklist before requesting a review
+
+- [ ] I have linked my PR to an issue ([instruction](https://docs.github.com/en/issues/tracking-your-work-with-issues/linking-a-pull-request-to-an-issue))
+- [ ] My issue clearly describes the problem/feature/proposal, with diagrams/charts/table/code if possible
+- [ ] I have performed a self-review of my code
+- [ ] I have added thorough tests.
+- [ ] I have added docstrings for all the functions/methods I implemented
+
+## ⭐️ Do you enjoy contributing to Colossal-AI?
+
+- [ ] 🌝 Yes, I do.
+- [ ] 🌚 No, I don't.
+
+Tell us more if you don't enjoy contributing to Colossal-AI.