Added background argument to isle skin
Added promo-button skin
Promo button size and gradients fix
Docs fix
Fix promo-button tests
Added test for domik, version up
Merge branch 'pr/43'

* pr/43:
  Fix promo-button tests
  Docs fix
  Promo button size and gradients fix
  Added promo-button skin
  Added background argument to isle skin
Fixed tests for promo-button according to the new stylobate
Changelog up