Document merged but unreleased changes in changelog.

[timbotimbo]

Description

Some small changes have been merged into the master branch, but have yet to be released in a plugin or unitypackage update. I documented them in the changelogs, to avoid these changes from being missed in the future or accidentally reverted.

Type of Change

• [ ] ✨ New feature (non-breaking change which adds functionality)
• [ ] 🛠️ Bug fix (non-breaking change which fixes an issue)
• [ ] ❌ Breaking change (fix or feature that would cause existing functionality to change)
• [ ] 🧹 Code refactor
• [ ] ✅ Build configuration change
• [x] 📝 Documentation
• [ ] 🗑️ Chore

[timbotimbo]

Looks like these plugin changes:

• [iOS] Fix Unity not receiving Lifecycle events on iOS. #704
• [Android] Remove the white background color to allow Unity transparency like on iOS. #719
• [Web] Replace webview package to get webview_flutter from 2.x to 4.x. #761
• Readme updates & example compatibility fixes.

Got released on pub.dev in 2022.2.1, with the changelog

• Minor improvements