v1.3.0-dev04

Fourth dev pre-release toward v1.3.0.

Fixed

• A stale or unknown session id could spawn a duplicate live session on every set edit, and deleting a session didn't stick after the next sync (#87, diagnosed by @kgenerozov). Full technical breakdown in the CHANGELOG.

Security

• Bumped multer and nodemailer for open Dependabot advisories.