Update build script to use Gulp 4 Syntax

[AlexGStapleton]

The build script requires a very specific unsupported version of node.js, and a lot of the dependencies are outdated. I mentioned to Greg the idea of updating the dependencies to the latest versions, and he suggested updating everything to use the latest version of Gulp. This will allow for better overall performance and better compatibility with newer versions of Node.js.

From memory, there are a few dependencies that we use that are no longer supported overall, such as gulp-request, so we may need to swap them out with better support alternatives. I'll update this issue with a list of dependencies in the comments that are outdated with possible alternatives.