(maint) Use latest Faraday/webmock, update specs

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.

spec/spec_helper.rb

@@ -2,6 +2,7 @@
 
 require 'simplecov'
 require 'coveralls'
+require 'base64'
 
 SimpleCov.formatter = SimpleCov::Formatter::MultiFormatter.new([
                                                                  SimpleCov::Formatter::HTMLFormatter,
@@ -26,3 +27,19 @@ RSpec.configure do |config|
   config.tty = true
   config.formatter = :documentation
 end
+
+def get_headers(username: nil, password: nil, token: nil, content_type: nil, content_length: nil)
+  headers = {
+    'Accept'          => '*/*',
+    'Accept-Encoding' => /gzip/,
+    'User-Agent'      => /Faraday/,
+  }
+  if username && password
+    auth = Base64.encode64("#{username}:#{password}").chomp
+    headers['Authorization'] = "Basic #{auth}"
+  end
+  headers['X-Auth-Token'] = token if token
+  headers['Content-Type'] = content_type if content_type
+  headers['Content-Length'] = content_length.to_s if content_length
+  headers
+end