remove julia v1.6 code

Author: ogauthe

NDTensors/src/lib/LabelledNumbers/src/labelledunitrange.jl

@@ -17,16 +17,6 @@ unlabel_type(::Type{<:LabelledUnitRange{Value}}) where {Value} = Value
 function Base.AbstractUnitRange{T}(a::LabelledUnitRange) where {T}
   return AbstractUnitRange{T}(unlabel(a))
 end
-# Used by `CartesianIndices` constructor.
-# TODO: Seems to only be needed for Julia v1.6, maybe remove once we
-# drop Julia v1.6 support.
-function Base.OrdinalRange{T1,T2}(a::LabelledUnitRange) where {T1,T2<:Integer}
-  return OrdinalRange{T1,T2}(unlabel(a))
-end
-# Fix ambiguity error in Julia v1.10.
-function Base.OrdinalRange{T,T}(a::LabelledUnitRange) where {T<:Integer}
-  return OrdinalRange{T,T}(unlabel(a))
-end
 
 # TODO: Is this a good definition?
 Base.unitrange(a::LabelledUnitRange) = a