OrderedDict missing `last`

[jmigual]

OrderedDict provides a first method but does not provide a last method:

julia> a = OrderedDict(1 => "a", 2 => "b")
OrderedDict{Int64, String} with 2 entries:
  1 => "a"
  2 => "b"

julia> first(a)
1 => "a"

julia> last(a)
ERROR: MethodError: no method matching lastindex(::OrderedDict{Int64, String})
Closest candidates are:
  lastindex(::Any, ::Any) at ~\scoop\apps\julia\current\share\julia\base\abstractarray.jl:373
  lastindex(::Union{SortedDict, SortedMultiDict, SortedSet}) at ~\.julia\packages\DataStructures\izXYB\src\tokens2.jl:19
  lastindex(::Number) at ~\scoop\apps\julia\current\share\julia\base\number.jl:90
  ...
Stacktrace:
 [1] last(a::OrderedDict{Int64, String})
   @ Base .\abstractarray.jl:473
 [2] top-level scope
   @ REPL[26]:1