Add SavedState subsection to PR template (#5389)

## Release Notes
N/A

Author: MatkovIvan

.github/PULL_REQUEST_TEMPLATE.md

@@ -11,4 +11,4 @@ Describe proposed changes and the issue being fixed
 ### Section - Subsection
 - Describe change in format https://github.com/JetBrains/compose-multiplatform/blob/master/tools/changelog/PR_FORMAT.md
   - Sections: Highlights, Known Issues, Breaking Changes, Migration Notes, Features, Fixes
-  - Subsections: Multiple Platforms, iOS, Desktop, Web, Android, Resources, Gradle Plugin, Lifecycle, Navigation
+  - Subsections: Multiple Platforms, iOS, Desktop, Web, Android, Resources, Gradle Plugin, Lifecycle, Navigation, SavedState