`geos::Geometry` to `ewkt` panic

[lewiszlw]

    #[test]
    fn geos_to_ewkt() {
        use geozero::GeozeroGeometry;
        use geozero::ToWkt;

        let wkt = "POINT(1 1)";
        let mut ggeom = geos::Geometry::new_from_wkt(wkt).unwrap();

        println!("ewkt: {}", ggeom.to_ewkt(ggeom.srid()).unwrap());
    }

this test will panic with

thread 'function::as_ewkt::tests::geos_to_ewkt' panicked at /usr/local/cargo/registry/src/index.crates.io-6f17d22bba15001f/geos-8.3.1/src/coord_seq.rs:498:9:
assertion failed: self.nb_dimensions >= 3