chore(github): add pull request template

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,52 @@
+<!--- Thank you for contributing to rustypaste! -->
+
+## Description
+
+<!--- Describe your changes in detail -->
+
+## Motivation and Context
+
+<!--- Why is this change required? What problem does it solve? -->
+<!--- If it fixes an open issue, please link to the issue here. -->
+
+## How Has This Been Tested?
+
+<!--- Please describe in detail how you tested your changes. -->
+<!--- Include details of your testing environment, and the tests you ran to -->
+<!--- see how your change affects other areas of the code, etc. -->
+
+## Changelog Entry
+
+<!--- Please write the changelog entry for these changes. -->
+<!--- Follow the <https://keepachangelog.com/en/1.0.0/> format. -->
+<!--- Use one of the Added, Changed, Deprecated, Removed, Fixed, and Security headers accordingly. -->
+<!-- For example:
+```
+### Added
+
+- Add a middleware for checking the content length
+  - Before, the upload size was checked after full upload which was clearly wrong.
+```
+-->
+
+## Types of Changes
+
+<!--- What types of changes does your code introduce? Put an `x` in all the boxes that apply: -->
+
+- [ ] Bug fix (non-breaking change which fixes an issue)
+- [ ] New feature (non-breaking change which adds functionality)
+- [ ] Breaking change (fix or feature that would cause existing functionality to change)
+- [ ] Documentation (no code change)
+- [ ] Refactor (refactoring production code)
+- [ ] Other <!--- (provide information) -->
+
+## Checklist:
+
+<!--- Go over all the following points, and put an `x` in all the boxes that apply. -->
+
+- [ ] My code follows the code style of this project.
+- [ ] I have updated the documentation accordingly.
+- [ ] I have formatted the code with [rustfmt](https://github.com/rust-lang/rustfmt).
+- [ ] I checked the lints with [clippy](https://github.com/rust-lang/rust-clippy).
+- [ ] I have added tests to cover my changes.
+- [ ] All new and existing tests passed.