Add updated Let's Go, Sword/Shield icons

[xAlien95]

Let's Go and Sword/Shield added enlarged icons for last evolutionary Pokémon stages, e.g. for Charizard or Gigalith.

Since generation 8 sprites are already "enlarged", it would be nice to update the old generation ones too.

[ami]

if someone wants to help us with recolored shiny versions of these enlarged sprites, we'd be happy to swap them out! otherwise, we'll probably keep the old sprites for now.

[Jacs720]

There is this project that fits perfectly with this request. https://github.com/msikma/pokesprite