replace deprecated IsPositive example with IsStrictlyPositive in Readme
replace deprecated IsPositive example with IsStrictlyPositive in Readme

tpierrain/NFluent,tpierrain/NFluent,tpierrain/NFluent,dupdob/NFluent,dupdob/NFluent,dupdob/NFluent,NFluent/NFluent,NFluent/NFluent