Add sets for performers (#54)

* add Sets

* add set to generate function

* add set to generate function

* fix variable type

* fix set-ids

* Update doc comment - add sets variable

* fix code style

* update tests

Use iterable to allow generators (#53)

* use iterable to allow generators

* ci/cd: bump action versions

* tests: update phpunit and faker

tests: update phpunit and faker

tests: use max 10 version

* phpcs: update min version

* phpcs: ignore env to works with php > 8.0

add outlets for SberMegaMarket (#49)

* add outlets for SberMegaMarket


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Co-authored-by: Diman <dimawar@mail.ru>

Date format changed (RFC 3339) (#46)

https://yandex.ru/support/marketplace/assortment/auto/yml.html#yml_catalog

Added a new field Dimensions (issuse #40) (#41)

Added a new field purchase_price to Offer (issuse #29) (#39)

Remove 8.0 from tests

`$tmpFile`. `$writer` and `$settings` of Generator class made protect…

…ed (#32)

to be possible extend Generator class and override methods using those class variables.

Add enable_auto_discounts property to offer and shop info (#31)

* add autoDiscount property to SiteInfo

* add autoDiscount property to AbstractOffer

* add tests

Code style fixes