Summary:
Original commit changeset: 05d13aca7145
Attempt to upgrade `electron` as it instacrashed; `electron-builder` version 22.1.0 didn't sign package correctly and caused the instacrash,
Reduced the version to 21.2.0 (latest).
Reviewed By: passy, nikoant
Differential Revision: D18954671
fbshipit-source-id: bc2dbd4fec9afb51d9a535974651b13d195407b4