Updated dependencies

[NickCis]

Hi Derrick, first of all thanks for the package it really helped me!.

I've updated some dependencies. The motivation was that geohash-poly depends on turf-intersect which depends on jsts. When bundling geohash-poly with webpack in order to use it on a browser, the jsts package weighed too much. Luckily, new @turf/intersect doesn't depend on the jsts package, so I don't have the weight problem.

I have run tests and I got some failures, I was wondering if you can help me in order to debug them:

geohash-poly ➞  standard ➞  should geohash over split threshold shape. Precision 1.
geohash-poly ➞  standard ➞  should geohash over split threshold shape. Precision 1. ✘   
geohash-poly ➞  standard ✘  
geohash-poly ✘  

FAILURE: 184/185 tests ran successfully; 1 failed, 0 incomplete, 1 errors

Error #1:
geohash-poly ➞  standard ➞  should geohash over split threshold shape. Precision 1.
Error: poly1 and poly2 must be either polygons or multiPolygons
    at Object.intersect (/home/nickcis/repos/geohash-poly/node_modules/@turf/intersect/index.js:106:15)
    at preparePoly (/home/nickcis/repos/geohash-poly/index.js:140:33)
    at makeRow (/home/nickcis/repos/geohash-poly/index.js:160:5)
    at Hasher.getNextRow (/home/nickcis/repos/geohash-poly/index.js:223:5)
    at /home/nickcis/repos/geohash-poly/index.js:93:10
    at Object.async.whilst (/home/nickcis/repos/geohash-poly/node_modules/async/lib/async.js:619:13)
    at Hasher._read (/home/nickcis/repos/geohash-poly/index.js:90:9)
    at Hasher.Readable.read (_stream_readable.js:453:10)
    at resume_ (_stream_readable.js:929:12)
    at process._tickCallback (internal/process/next_tick.js:63:19)

Thanks in advance!