dart pub downgrade

Use cached packages instead of accessing the network

--offline

Do not use cached packages instead of accessing the network

Report what dependencies would change but don't change any

Name	Description
`-h, --help`	Print this usage information
`--offline`	Use cached packages instead of accessing the network
`--no-offline`	Do not use cached packages instead of accessing the network
`-n, --dry-run`	Report what dependencies would change but don't change any