replaced Array.isArray with isarray package

[wagerfield]

This PR offers better backwards compatibility for environments that don't support Array.isArray.

The isarray package is the defacto way of performing this type check (46 million monthly downloads) so it makes sense that isobject should use it as part of its check.

[jonschlinkert]

The isarray package is the defacto way of performing this type check (46 million monthly downloads)

Yeah, I think a huge portion of those downloads is from a previous version of this package.

How likely is it for this to be used in a browser that doesn't support Array.isArray, without having gone through a build-step with something like webpack or browserify first?

Especially given that Array.isArray is just one of many methods and javascript features that won't be available in browsers that don't support JavaScript 1.8.5. It seems unlikely for modern JavasScript to used in older browsers without also having the necessary polyfills.

Any thoughts on this?

[wtgtybhertgeghgtwtg]

I don't think there's any supported browser or node version that does not have Array.isArray.

[jonschlinkert]

Closing, I don't see why this would be needed.