bump reactiscriptsixify dep version
bump reactiscriptsixify dep version

(to version that does the es6 transforms by default)

Test Plan:
none

ariabuckles/perseus,chirilo/perseus,alexristich/perseus,daukantas/perseus,junyiacademy/perseus,iamchenxin/perseus,daukantas/perseus,iamchenxin/perseus,ariabuckles/perseus,ariabuckles/perseus,chirilo/perseus,ariabuckles/perseus,learningequality/perseus,abe4mvp/perseus,huangins/perseus,abe4mvp/perseus,junyiacademy/perseus,sachgits/perseus,sachgits/perseus,huangins/perseus,alexristich/perseus,learningequality/perseus