This update cannot be done by the nixpkgs bot, as
the structure of the project has been changed, so why wait.
The mautrix-meta project has been moved under "cmd/mautrix-meta"
There is also "cmd/lscli", but since this package is mainly
about mautrix-meta, I think we can stay with this specific cmd.
If we wanted, we could switch to both of them by removing this
`subPackages` attribute.
This contains many improvements, some notable changes:
- A handful of backfill improvements.
- Memory usage improvements for video download.
- Support for more event types.
See full list: https://github.com/mautrix/meta/compare/v0.2.0...v0.3.0
