fast_i18n v5.0.0

This release mostly focuses on simplifications of build.yaml.

• Breaking: builder name renamed from fast_i18n:i18nBuilder to fast_i18n
• Breaking: plural auto detection is on by default (auto: cardinal)
• Breaking: fallback strategy option strict is now none
• Breaking: key paths in build.yaml must be cased according to key_case if specified
• Breaking: your project must be null safe
• feat: generated file follows lint guidelines
• feat: add support for linked translations, e.g. Welcome to @:appName

You can read the detailed migration guide here.