Use Octokit::Client for both .com and Enterprise

Octokit:EnterpriseAdminClient is only meant to be used for GHE admin
panel endpoints, such as Admin Stats, Management Console, etc.

This repairs GHE functionality by passing the API endpoint parameters
into Octokit::Client and letting it handle the rest.

lib/github_changelog_generator/octo_fetcher.rb

@@ -23,7 +23,7 @@ module GitHubChangelogGenerator
     # @option options [Boolean] :http_cache Use ActiveSupport::Cache::FileStore to cache http requests
     # @option options [Boolean] :cache_file If using http_cache, this is the cache file path
     # @option options [Boolean] :cache_log If using http_cache, this is the cache log file path
-    def initialize(options = {}) # rubocop:disable Metrics/CyclomaticComplexity
+    def initialize(options = {})
       @options      = options || {}
       @user         = @options[:user]
       @project      = @options[:project]
@@ -40,8 +40,7 @@ module GitHubChangelogGenerator
       @github_options[:access_token] = @github_token unless @github_token.nil?
       @github_options[:api_endpoint] = @options[:github_endpoint] unless @options[:github_endpoint].nil?
 
-      client_type = @options[:github_endpoint].nil? ? Octokit::Client : Octokit::EnterpriseAdminClient
-      @client     = client_type.new(@github_options)
+      @client = Octokit::Client.new(@github_options)
     end
 
     def init_cache