Phaser declared as a devDependency

[coulgreer]

Current Behavior 😯

As the title says: the Phaser package is declared under devDependencies instead of dependencies in package.json.

Expected Behavior 🤔

Phaser should be declared under dependencies.

Steps to Reproduce 🕹

Look at the current package.json.

Context 🔦

If a user of this template creates another package from this template package, Phaser -- the core of the template -- would be excluded when running npm install "$package". Although this may seem like a niche issue, it is also accompanied with an easy and necessary solution. This, too, will align this template with its vanilla JavaScript sibling template.