Remove the `approx` feature requirement for `geo-types` in the `geo` crate?

[frewsxcv]

Do we need this?

https://github.com/georust/geo/blob/a3c2094990f87ac9e31420893bd2c1a0e43711e8/geo/Cargo.toml#L19

Could it just be a feature we enable in tests?

[michaelkirk]

I don't think I'm personally using it for anything.

If other people are trying to do things like:

use approx::relative_eq;
use geo::Polygon;
assert_relative_eq!(poly1, poly2)

Without relying on geo-types directly, this will break for them. For them we could add a pass through feature.

I'm curious - is this blocking you from doing something, or just trying to keep things svelte?