update gem_is_bundled to has_gem
update gem_is_bundled to has_gem

cmaggard/heroku-buildpack-turbo-sprockets,jonseaberg/heroku-buildpack-turbo-sprockets,cmaggard/heroku-buildpack-turbo-sprockets,vhx/heroku-buildpack,jonseaberg/heroku-buildpack-turbo-sprockets,vhx/heroku-buildpack,ndbroadbent/heroku-buildpack-turbo-sprockets,ndbroadbent/heroku-buildpack-turbo-sprockets