docs(datepicker): add since tags

[danielleroux]

🆕 What is the new behavior?

• Add since tags

🏁 Checklist

A pull request can only be merged if all of these conditions are met (where applicable):

• 🦮 Accessibility (a11y) features were implemented
• 🗺️ Internationalization (i18n) - no hard coded strings
• 📲 Responsiveness - components handle viewport changes and content overflow gracefully
• 📄 Documentation was reviewed/updated (yarn docs)
• 🧪 Unit tests were added/updated and pass (yarn test)
• 📸 Visual regression tests were added/updated and pass (yarn visual-regression)
• 🧐 Static code analysis passes (yarn lint)
• 🏗️ Successful compilation (yarn build, changes pushed)

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