Revert nuget spec to last release.
Revert nuget spec to last release.

maherkassim/UnitsNet,anjdreas/UnitsNet,anjdreas/UnitsNet,neutmute/UnitsNet,Tirael/UnitsNet,maherkassim/UnitsNet,BoGrevyDynatest/UnitsNet,BrandonLWhite/UnitsNet,BrandonLWhite/UnitsNet