public static DateTime? GetMaximumBuildDate();
Retrieves a maximum build date from a current license key. Returned
Nullable<DateTime> has a value if a current license key c ontains maximum build date.
A license key becomes expired and ArmDot.Client.Api.GetLicenseState returns
LicenseKeyState.MaximumBuildDateExpired for binaries, built after maximum build date.
ArmDot.Client.Api.PutKey must have been already called.