ci: Test with CPython 3.13.

Author: seifertm

.github/workflows/main.yml

@@ -62,7 +62,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu, windows]
-        python-version: ['3.8', '3.9', '3.10', '3.11', '3.12']
+        python-version: ['3.8', '3.9', '3.10', '3.11', '3.12', 3.13.0-beta.3]
 
     steps:
     - uses: actions/checkout@v4

tox.ini

@@ -1,6 +1,6 @@
 [tox]
 minversion = 3.14.0
-envlist = py38, py39, py310, py311, py312, pytest-min, docs
+envlist = py38, py39, py310, py311, py312, py13, pytest-min, docs
 isolated_build = true
 passenv =
     CI
@@ -42,4 +42,5 @@ python =
     3.10: py310
     3.11: py311
     3.12: py312
+    3.13: py313
     pypy3: pypy3