Sauce Labs badge showing unknown karma.js

When including the Status Badge in a project's README.md file using:

[![Sauce Test Status](http://ift.tt/2dAIvGm)](http://ift.tt/2dAH2Q3)

It is displaying this:

instead of this:

Relevant devDependencies in the package.json file:

"karma": "^1.7.0",
"karma-chrome-launcher": "^2.1.1",
"karma-jasmine": "^1.1.0",
"karma-sauce-launcher": "^1.1.0",

Relevant config settings in the karma.conf.js file:

singleRun: process.env.CI,
sauceLabs: {
  testName: 'Web App Tests'
},
customLaunchers: customLaunchers,
reporters: process.env.CI ? ['dots', 'saucelabs'] : ['progress']