Upgrade bevy_ecs_tilemap to 0.8

[bardt]

I made minimal changes to the code to make it compile.

I assume TilemapTexture::Single is equivalent to the TilemapTexture behaviour from 0.7.

Closes #121

[Trouv]

Thanks for doing this work! It seems the way that bevy_ecs_tilemap positions the tiles in the world has changed pretty drastically, which has messed up all the examples in some way. I expect adjusting to this to be a somewhat involved change so I'm happy to merge this now and adjust in future PRs unless you want to try looking into it in this PR

[bardt]

@Trouv I will look into it this evening. Not sure if I will manage to solve it quickly.

[Trouv]

@Trouv I will look into it this evening. Not sure if I will manage to solve it quickly.

No worries - I can just merge this unless you feel like you're close. It probably makes sense to split up the change into multiple PRs anyway

[bardt]

@Trouv I don't think I'm super close. So feel free to merge this one.

I'm currently learning the relations between TileMapBundle, TileBundle, and SpatialBundle, and trying to understand what has changed between 0.7 and 0.8 of bevy_ecs_tilemap.