This unpins Faraday and webmock, and updates specs so that the Faraday changes (primarily including auth in the header rather than in the URL) is reflected.
This adds Dependabot to keep things updated and Coveralls so we can see
how code coverage changes over time. Coveralls / SimpleCov are
configured so that both the SimpleCov html report and the Coveralls
report are generated. This facilitates easily seeing coverage locally in
addtion to via CI.