5_zero2prod/3_chapter/3_11.md: Age -> Birthday year/date

[TheBestTvarynka]

https://github.com/rust-lang-ua/rustcamp/blob/master/5_zero2prod/3_chapter/3_11.md

Problem to solve

// todo

Proposal

Change Age to Birthday date.

Prior art

Alternatives

Links & references