Add support for skipping on systems with PowerShell versions lower than 3

[tvories]

We unfortunately still have systems that have PowerShell versions lower than 3. Ideally, the fact should check $PSVersiontable before attempting to run.

I can submit a PR for this later, just wanted to add an issue before I forgot.

We have provided our own ConvertTo-JSON functions in our older systems, though I'm not sure if there's enough of a justification to support systems this old. At least with the version check, it won't error on these systems.