In this challenge, you have to find the distance between two points placed on a Cartesian plane. Knowing the coordinates of both the points, you have to apply the Pythagorean theorem to find the distance between them.

Given two object literals a and b being the two points coordinates (x and y), implement a function that returns the distance between the points, rounded to the nearest thousandth.
getDistance({x: -2, y: 1}, {x: 4, y: 3}) ➞ 6.325
getDistance({x: 0, y: 0}, {x: 1, y: 1}) ➞ 1.414
getDistance({x: 10, y: -5}, {x: 8, y: 16}) ➞ 21.095
a to b.