deps: upgrade deep-equal@1.1.0->2.1.0

[legobeat]

No description provided.

[mcmire]

This seems to add a lot more dependencies. Is that okay? (I assume maybe so in this case, as maybe they are small, but just want to check.)

[legobeat]

To address thew question about size, when measured by yarn install --prod: This commit is an increase of 3284 b (27368 - 24084).

The main contributor here is object.assign clocking in at 1284b. It seems the maintainer is optimizing heavily for backwards-compatibility: inspect-js/node-deep-equal#100

This package is using babel to address that. I think you're right @mcmire that this one isn't worth it. Thank you for catching that!

Is object.assign et al worth filling in for still? Might be worth replacing deep-equal alltogether for something more appropriate.

Alternatively, 2.0.2 is the last version not depending on object.assign.

[legobeat]

(then on the other hand, in context of metamask-extension, we already have a runtime dependency on the same version of object.assign 🤷 )

[legobeat]

@mcmire I resurrected this in #94, with the ambition of getting out a non-breaking maintenance release before deprecating nodejs v12, which would also unlock bringing this in line with metamask-module-template.