Mirroring Vendored Crates

[KeepSummerSaf3]

Args for #71 appear to be inconsistent with the readme documentation regarding synchronization of vendored crates. Maybe I am missing something.

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Sync Select Dependencies Optionally, panamax can be told to only grab crates needed to build a singular project. cargo vendor is used to create a folder with all needed dependencies, then a panamax command can parse the created directory and only grab those crates and versions.

Only grab crates needed for panamax, as an example

$ cargo vendor
$ panamax sync my-mirror vendor

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Non-working option:

$panamax sync offline-mirror vendor
error: unexpected argument 'vendor' found

Usage: panamax sync [OPTIONS] <PATH>

Working option:

$panamax sync --vendor-path ./vendor offline-mirror
Syncing Rustup repositories...