✅ also test under Python 3.13 and with free-threading

Signed-off-by: burgholzer <burgholzer@me.com>

pyproject.toml

@@ -267,7 +267,6 @@ skip = "*-musllinux_*"
 archs = "auto64"
 test-groups = ["test"]
 test-command = "pytest {project}/test/python"
-test-skip = ["cp313*"] # skip testing on Python 3.13 until our dependencies are ready
 build-frontend = "build[uv]"
 enable = ["cpython-freethreading"]
 manylinux-x86_64-image = "manylinux_2_28"