[GRASS-git] [OSGeo/grass] f08fdc: g.extension: Remove six dependency (#2828)

[Vaclav Petras]

  Branch: refs/heads/main
  Home:   https://github.com/OSGeo/grass
  Commit: f08fdcdd1c0a1ec5ac9d1df20a7f34b863e9f98c
      https://github.com/OSGeo/grass/commit/f08fdcdd1c0a1ec5ac9d1df20a7f34b863e9f98c
  Author: Vaclav Petras <wenzeslaus at gmail.com>
  Date:   2023-02-14 (Tue, 14 Feb 2023)

  Changed paths:
    M scripts/g.extension.all/g.extension.all.py
    M scripts/g.extension/g.extension.py

  Log Message:
  -----------
  g.extension: Remove six dependency (#2828)

* Removes imports from six, uses standard Python 3 imports.
* Removes Python <=2.4 ElementTree import.
* Removes future print_function imports.

Removes six only from g.extension and g.extension.all. Leaves the rest as is.