I know that vscode itself can not be added because it contains proprietary software. However I’d say adding VSCodium to swupd could be possible since it is a fork of the opensource vscode project. I’ve been using for a while and it works flawlessly and further more is something that IMHO all vscode users would “change” to.
VSCodium as stated by them is open source “These binaries are licensed under the MIT license. Telemetry is disabled.”. This information can be found both at https://vscodium.com/ and https://github.com/VSCodium/vscodium.