go mod tidy fails

[sumnerevans]

Running go mod tidy fails on main.

$ go mod tidy
go: finding module for package go.mau.fi/mautrix-signal/pkg/signalmeow/protobuf
go: finding module for package go.mau.fi/mautrix-signal/pkg/signalmeow
go.mau.fi/mautrix-signal imports
        go.mau.fi/mautrix-signal/pkg/signalmeow: cannot find module providing package go.mau.fi/mautrix-signal/pkg/signalmeow: unrecognized import path "go.mau.fi/mautrix-signal/pkg/signalmeow": reading https://go.mau.fi/mautrix-signal/pkg/signalmeow?go-get=1: 404 Not Found
go.mau.fi/mautrix-signal imports
        go.mau.fi/mautrix-signal/pkg/signalmeow/protobuf: cannot find module providing package go.mau.fi/mautrix-signal/pkg/signalmeow/protobuf: unrecognized import path "go.mau.fi/mautrix-signal/pkg/signalmeow/protobuf": reading https://go.mau.fi/mautrix-signal/pkg/signalmeow/protobuf?go-get=1: 404 Not Found

There's a go.mod and go.sum in pkg/signalmeow, which I think is the cause of
this.

[tulir]

It's not directly related to the separate go modules (it can be fixed), but if it was fixed then it'd add annoying extra entries to the main go.mod which would always be outdated by definition