feat(Avatar): Enhance type of Avatar component's props

[hckhanh]

I think that the type of src, alt and text should be enhanced to make it more friendly with TypeScript

🔗 Linked issue

❓ Type of change

• 📖 Documentation (updates to the documentation or readme)
• 🐞 Bug fix (a non-breaking change that fixes an issue)
• 👌 Enhancement (improving an existing functionality)
• ✨ New feature (a non-breaking change that adds functionality)
• 🧹 Chore (updates to the build process or auxiliary tools and libraries)
• ⚠️ Breaking change (fix or feature that would cause existing functionality to change)

📚 Description

📝 Checklist

• I have linked an issue or discussion.
• I have updated the documentation accordingly.

[benjamincanac]

I don't think this is necessary, the prop types should already be inferred automatically: https://vuejs.org/guide/typescript/overview.html#definecomponent

[hckhanh]

@benjamincanac Did you get any warnings about this in VSCode or WebStorm? I got a warning about the type mismatch in WebStorm.