py-more-itertools: updated to 8.13.0

8.13.0
------

* New functions
    * The :func:`subslices` recipe from the `itertools` docs was added (thanks to rhettinger)

* Changes to existing functions
    * The :func:`ichunked` function is now more efficient (thanks to hjtran0 and seanmacavaney)
    * The :func:`difference` function is now more efficient (thanks to Masynchin)
    * The :func:`grouper` recipe now has more features, mirroring the one in the `itertools` docs (thanks to rhettinger)

* Other changes
    * Some documentation issues were fixed (thanks to medvied and Freed-Wu)
    * The `more_itertools` package is now built with `flit` (thanks to mgorny)

(adam)