drop: Python 3.9 and 3.10 support, update README and tox configuration

Author: FelixTheC

README.md

@@ -1,7 +1,7 @@
 # strongtyping-pyoverload
-[![Python 3.9](https://img.shields.io/badge/python-3.9-blue.svg)](https://www.python.org/downloads/release/python-390/)
-[![Python 3.10](https://img.shields.io/badge/python-3.10-blue.svg)](https://www.python.org/downloads/release/python-3100/)
 [![Python 3.11](https://img.shields.io/badge/python-3.11-blue.svg)](https://www.python.org/downloads/release/python-3110/)
+[![Python 3.12](https://img.shields.io/badge/python-3.12-blue.svg)](https://www.python.org/downloads/release/python-3120/)
+[![Python 3.13](https://img.shields.io/badge/python-3.13-blue.svg)](https://www.python.org/downloads/release/python-3130/)
 [![Code style: black](https://img.shields.io/badge/code%20style-black-000000.svg)](https://github.com/psf/black)
 [![Imports: isort](https://img.shields.io/badge/%20imports-isort-%231674b1?style=flat&labelColor=ef8336)](https://pycqa.github.io/isort/)
 ![Python application](https://github.com/FelixTheC/py-overload/workflows/Python%20application/badge.svg)

tox.ini

@@ -1,5 +1,5 @@
 [tox]
-envlist = py310,py311,py312,py313
+envlist = py311,py312,py313
 
 [testenv]
 deps = pytest-cov