feat: Add an alias for same-package fonts

[nikodembernat]

Description

Added an alias for same-package fonts to support running golden tests in packages (e.g. design systems).

Fixes #142

The specified package:yaml lower version constraint is equal to package:yaml pinned in Flutter 3.16 (min. supported version) to avoid version conflicts.

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
• 📝 Documentation
• 🗑️ Chore

[nikodembernat]

Not a big fan of reading package name from pubspec.yaml, if you have a better solution then I'm open to suggestions

[jeroen-meijer]

@btrautmann Haven't touched our package or used it as intensely as you guys probably have. Can you verify the validity of the business logic here?

Code itself LGTM.

[nikodembernat]

From what I see the new goldens are failing since they don't exist, someone with necessary permissions has to regenerate them if I understand the workflow correctly