[Docs] Adds pull request template

Docs/pull_request_template.md

@@ -0,0 +1,34 @@
+Mark the type contribution you are making:
+
+- [ ] Experimental feature (new functionality that can be selectively enabled/disabled)
+- [ ] Bug fix (non-breaking change which fixes an issue)
+
+# Description
+
+Summary of your changes, including: 
+
+* Why is this change necessary?
+* Why did you decide on this solution?
+
+# Testing
+
+List all iOS versions and devices you've tested this change on.
+
+**Example Configurations**:
+
+- iPhone 14, iOS 16.3.1
+- iPhone X, iOS 15.7.4
+
+# Checklist
+**General (All PRs)**
+- [ ] My code follows the style guidelines of this project
+- [ ] I have performed a self-review of my code
+- [ ] I have commented my code, particularly in hard-to-understand areas
+- [ ] My changes generate no new warnings
+- [ ] I've tested my changes with different device + OS version configurations
+
+**Experimental Feature-specific** 
+- [ ] Added property to `ExperimentalFeatures` struct annotated with `@Feature`
+- [ ] Uses `@Option`'s to persist all feature-related data
+- [ ] Locked *all* behavior changes behind `ExperimentalFeatures.shared.[feature].isEnabled` runtime check
+- [ ] Isolates changes to separate files as much as possible (e.g. via Swift extensions)