fix: generate a `CHANGELOG.md` for the `dart_pkg` and `flutter_pkg` templates

[Luckey-Elijah]

Description

dart.dev recommends packages have a CHANGELOG.md when uploaded to pub.dev.

I'm suggesting very_good create -t flutter_pkg <name> and very_good create -t dart_pkg <name> should both create CHANGELOG.md files.

dart create <name> generates a CHANGELOG.md:

## 1.0.0

- Initial version.

[felangel]

Hi @Luckey-Elijah 👋 Thanks for opening an issue!

We're working on revamping the Dart and Flutter package templates and they will include a CHANGELOG (among many other improvements in the near future). Thanks again and sorry for any inconvenience!

[Luckey-Elijah]

Sounds great! Looking forward to your very good changes 🙂

[Luckey-Elijah]

PS I did notice #385 but I'm not sure if they're quite duplicates. That one is requesting a full-featured changelog configuration tool. I'd just like to see the file created 🙂

[renancaraujo]

This was fixed by #592