Switch back to pendulum (#492, #482)

v3.1.0 now has Py3.13 support Import directly pendulum module

Revert "Switch from pendulum to arrow (#492 (closed), #482 (closed))"

This reverts commit c732e79d.

Close #492 (closed).

docs/contributing/index.md

@@ -52,7 +52,7 @@ Please read their documentations on how to use them the best possible.
     - Feel free to contribute upstream to share the code with other Python programs
 - [Click](https://click.palletsprojects.com/#documentation)
     - [Rich-Click](https://github.com/ewels/rich-click)
-- [Arrow](https://arrow.readthedocs.io/)
+- [Pendulum](https://pendulum.eustace.io/docs/)
 - [texttable](https://github.com/foutaise/texttable/#documentation)
 
 ## Pre-commit hooks