Add a CLI flag to skip Updates.pak when unpacking the game

[zrckr]

This makes possible to unpack resources from older versions of the game that may not have this file.

[Jenna1337]

Isn't the --unpack argument capable or unpacking individual PAK files? I don't see why we would need to add an argument to exclude certain files. If anything, I think there should be a flag to skip missing PAK files instead of throwing exceptions.

[Krzyhau]

I agree that this is not ideal solution. I think checking whether we ran a command in a game directory by making sure all packages exist was kind of a dumb move from me, and it should just attempt to unpack every package archive on predefined list without throwing an exception (although sending a warning as an alternative would be nice).

[zrckr]

I suggest a solution: scan all available files in the folder and generate a list of them, and make an exception for Updates.pak to unpack it last, if it exists. And issue a warning about its absence.