Allow pydict accept Pair args

[mkitti]

Create a method pydict(pairs::Pair...) similar to Dict(::Pair...).

This allow for the following usage.

julia> using PythonCall

julia> Dict("a" => 5, "b" => 6)
Dict{String, Int64} with 2 entries:
  "b" => 6
  "a" => 5

julia> pydict("a" => 5, "b" => 6)
Python: {'a': 5, 'b': 6}

[mkitti]

@cjdoris There seems to be an issue with Python 3.13 per the failing test.

xref: JuliaLang/julia#58475