Summary: This way we don't need to depend on Sandcastle configurations. amurawska pointed out that the header in `generate-changelog.js` indicates it must be run with Node 6, but trying to do so actually raises a Syntax error.
Reviewed By: mweststrate
Differential Revision: D23904875
fbshipit-source-id: 264f3b16d64ebfbae6afb0028715f67624166499