Clarify requirements for dir argument

[raven]

Follow on from #228

It is unclear when using the dir directory sharing that it requires guests to be running macOS 13 also. This PR tries to clarify that requirement in the help discussion output.

Is there a way to read back out from the VM either running or prior to booting to know the version macOS? Would be nicer to report the failure as opposed to requiring the user read the docs.

[edigaryev]

Is there a way to read back out from the VM either running or prior to booting to know the version macOS? Would be nicer to report the failure as opposed to requiring the user read the docs.

While it would be possible to write the macOS version at the VM installation step to the VM's configuration file and then consult it to figure out whether the --dir is supported.

However, it is still unclear what to do with VM's that were created without this logic. We can simply throw an error in this case and require the user to manually specify macOS version using tart set. Afterwards the --dir will continue to work.

@fkorotkov what do you think?

[fkorotkov]

I just checked and hardwareModel for Ventura VMs has min OS version set to 12 which is expected since you can run Ventura guests on Monterey hosts. So I guess there is no way to easily figure out the macOS version by just looking at an image.

@edigaryev suggestion might not work since one can initialize an OS update from within a VM. 🤔