Add more tests for base class overrides

[chris48s]

It would be great to have more tests for all of these overrides:

shields/services/base.js

Lines 240 to 249 in a265cab

	const {
	style,
	label: overrideLabel,
	logo: overrideLogo,
	logoColor: overrideLogoColor,
	logoWidth: overrideLogoWidth,
	link: overrideLink,
	colorA: overrideColorA,
	colorB: overrideColorB,
	} = overrides

At the moment we only have 2:

shields/services/base.spec.js

Lines 278 to 294 in 322f3ff

	describe('Overrides', function() {
	it('overrides the label', function() {
	const badgeData = DummyService._makeBadgeData(
	{ label: 'purr count' },
	{ label: 'purrs' }
	)
	expect(badgeData.text).to.deep.equal(['purr count', 'n/a'])
	})
	it('overrides the color', function() {
	const badgeData = DummyService._makeBadgeData(
	{ colorB: '10ADED' },
	{ color: 'red' }
	)
	expect(badgeData.colorB).to.equal('#10ADED')
	})
	})

[calebcartwright]

Is this still up for grabs? If so I'll give it a try as it looks simple enough (famous last words 😄)