Migration guide for VCC CLI users missing

[anatawa12]

Since there are no documentation what migrate project to 2022 in VCC does, I could not migrate my project on my macOS / Linux.

Please document what VCC does during migration somewhere

[anatawa12]

For your information, by removing unity just after starting VCC's unity migration starts, I found what VCC does and I posted what should we do for unity migration.
https://misskey.niri.la/notes/9nod7sk4sr

This may not be correct but migrating my project finished successfully with this steps.