chore: add a pull request template

.github/PULL_REQUEST_TEMPLATE/pull_request_template.md

@@ -0,0 +1,27 @@
+---
+name: Pull Request
+about: Propose changes to the codebase
+title: ''
+labels: ''
+assignees: ''
+
+---
+
+A similar PR may already be submitted!
+Please search among the [Pull request](https://github.com/sashabaranov/go-openai/pulls) before creating one.
+
+Thanks for submitting a pull request! Please provide enough information so that others can review your pull request.
+
+**Describe the change**
+Please provide a clear and concise description of the changes you're proposing. Explain what problem it solves or what feature it adds.
+
+**Describe your solution**
+Describe how your changes address the problem or how they add the feature. This should include a brief description of your approach and any new libraries or dependencies you're using.
+
+**Tests**
+Briefly describe how you have tested these changes. 
+
+**Additional context**
+Add any other context or screenshots or logs about your pull request here. If the pull request relates to an open issue, please link to it.
+
+Issue: #XXXX