Rename `BoxCode` with `Sku` for enhancing `Good`'s (#28)

Add `BoxCode` class (#27)

Add `Location` class for `locationCode()` method (#23)

Set `prefix` of receipt code changeable (#22)

Set `of()` to be nullable in `ReceiptCode` (#21)

Add receipt code classes (#20)

Provide `SetGood` class and parsed apis (#17)

Redesign all of codes (#16)

* Replace namespace from `GoodCodeParser` to `GoodCode`

* Remove useless classes

* Create a single class for all good types

* Prevent vscode setting files from `.gitignore`

* Update`README.md`

Make `GoodCodeType` enum and `GoodCodeType::of()` method (#15)

* Make `GoodCodeType` enum and `GoodCodeType::of()` method

* php 8.0 deprecated

Add static facade for easy-going (#14)

* Add static facade for easy-going

* Become English in test codes

* Update README