Remove rake task update_commit_count

lib/tasks/gitlab/update_commit_count.rake

-namespace :gitlab do
-  desc "GitLab | Update commit count for projects"
-  task update_commit_count: :environment do
-    projects = Project.where(commit_count: 0)
-    puts "#{projects.size} projects need to be updated. This might take a while."
-    ask_to_continue unless ENV['force'] == 'yes'
-
-    projects.find_each(batch_size: 100) do |project|
-      print "#{project.name_with_namespace.color(:yellow)} ... "
-
-      unless project.repo_exists?
-        puts "skipping, because the repo is empty".color(:magenta)
-        next
-      end
-
-      project.update_commit_count
-      puts project.commit_count.to_s.color(:green)
-    end
-  end
-end