Remove ESLint packages from dependencies

[swashcap]

I noticed that eslint packages are specified in dependencies:

nightwatch-extra/package.json

Lines 90 to 92 in 5f77e4c

	"eslint": "^3.12.2",
	"eslint-config-walmart": "^1.1.0",
	"eslint-plugin-filenames": "^1.1.0",

These are then downloaded alongside the testarmada-nightwatch-extra package, but don't appear to actually be used. Can these be moved to devDependencies?