fix!: changed type of `tileSize` to integer

[JaffaKetchup]

Fixes #1936.

There's no apparent reason that tileSize would be anything but an integer, since it is not possible to get tiles in fractional pixels. This PR relies on this assumption, and a different fix would be needed for #1936 if this assumption is not valid.

Note that this is breaking.

[JaffaKetchup]

We'll leave this to review and merge before a major upgrade.

[TesteurManiak]

As a way of making this less breaking, you could deprecate tileSize for a tileDimension parameter?

[JaffaKetchup]

As a way of making this less breaking, you could deprecate tileSize for a tileDimension` parameter?

I don't see why that wouldn't work, I'd be happy to do that if you think that's better.

[JaffaKetchup]

I've done what @TesteurManiak suggested.