[skip ci] Add python 3.13 to tox configuration

Author: jacobtylerwalls

doc/development_guide/contributor_guide/tests/launching_test.rst

@@ -30,7 +30,7 @@ tox
 You can also *optionally* install tox_ and run our tests using the tox_ package, as in::
 
     python -m tox
-    python -m tox -epy312 # for Python 3.12 suite only
+    python -m tox -epy313 # for Python 3.13 suite only
     python -m tox -epylint # for running Pylint over Pylint's codebase
     python -m tox -eformatting # for running formatting checks over Pylint's codebase
 

tox.ini

@@ -1,6 +1,6 @@
 [tox]
 minversion = 3.0
-envlist = formatting, py39, py310, py311, py312, pypy, benchmark
+envlist = formatting, py39, py310, py311, py312, py313, pypy, benchmark
 skip_missing_interpreters = true
 requires = pip >=21.3.1
 isolated_build = true