Add support for objects

[cameronhunter]

Hi,

Your package is my "go to" for computing the cartesian product of array values. Over the last few months I've found a repeated use-case for computing the cartesian product but with names rather than relying on array order. For example:

const elements = {
  color: ['black', 'white'],
  pattern: ['spots', 'stripes']
};

for (const { color, pattern } of product(elements)) {
  console.log(`The color is ${color} and the pattern is ${pattern}`);
}

I've mostly just been copying and pasting the code that computes this around, but since it uses cartesian-product I thought that perhaps it should just be a feature.

I had to update a few dependencies in the repository to get the linting and testing working, I tried to make as few changes as possible so as not to overwhelm the PR.

Thanks