Suggest: fallback to Get-GitStatus when Get-GitStatusFromCache failed.

[hcoona]

I'd suggest automatically fallback to lower performance but stable Get-GitStatus when Get-GitStatusFromCache failed, instead of totally not working and shows an "CACHE ERROR" here.

I suggest so because git-status-cache project currently not working well with git sparse checkout feature (https://github.com/cmarcusreid/git-status-cache/issues/27) & lfs feature (https://github.com/cmarcusreid/git-status-cache/issues/18). And both of them are blocked by libgit2 upstream, which could be a tough work to support them.