feat: add pull request template

.github/pull_request_template.md

@@ -0,0 +1,19 @@
+# New Preset: <NAME>
+
+<!-- comments -->
+
+## Screenshots (optional)
+
+<!-- Will be used in showcase -->
+
+# Checklist 
+
+Before submitting the PR, I checked:
+
+- [ ] I've only modified one preset
+- [ ] I've added the URL to my raw preset in `presets.json`
+- [ ] I've checked the format of each json files I modified
+- [ ] (optional) I've added screenshots
+- [ ] The preset name is following preset naming guidelines.
+
+Thanks for your submission we will review and merge it as quick as possible.