[Polaris-release] Update to Changelog for 4.8.0

[dleroux]

WHY are these changes introduced?

Update to Changelog for 4.8.0

WHAT is this pull request doing?

How to 🎩

🖥 Local development instructions
🗒 General tophatting guidelines
📄 Changelog guidelines

Copy-paste this code in playground/Playground.tsx:

import React from 'react';
import {Page} from '../src';

export function Playground() {
  return (
    <Page title="Playground">
      {/* Add the code you want to test in here */}
    </Page>
  );
}

🎩 checklist

• Tested on mobile
• Tested on multiple browsers
• Tested for accessibility
• Updated the component's README.md with documentation changes
• Tophatted documentation changes in the style guide
• For visual design changes, pinged one of @ HYPD, @ mirualves, @ sarahill, or @ ry5n to update the Polaris UI kit

[github-actions]

💦 Potential splash zone of changes introduced to src/**/*.tsx in this pull request:

No significant changes to src/**/*.tsx were detected.

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This comment automatically updates as changes are made to this pull request.
Feedback, troubleshooting: open an issue or reach out on Slack in #polaris-tooling.

[PabloVallejo]

Changelog looks good ✅