chore: officially support Python 3.13 (#104)

Adds Python 3.13 as a supported version in the classifiers that appear on PyPI and includes that version in the Tox tests to confirm compatibility

pyproject.toml

@@ -22,6 +22,7 @@ classifiers = [
     "Programming Language :: Python :: 3.10",
     "Programming Language :: Python :: 3.11",
     "Programming Language :: Python :: 3.12",
+    "Programming Language :: Python :: 3.13",
     "Topic :: Internet :: WWW/HTTP :: Dynamic Content",
     "Topic :: Software Development :: Libraries",
     "Topic :: Software Development :: Libraries :: Python Modules",
@@ -95,7 +96,7 @@ addopts = "--doctest-modules"
 legacy_tox_ini = """
 [tox]
 skipsdist = True
-envlist = py310,py311,py312,pypy3.10
+envlist = py310,py311,py312,py313,pypy3.10
 
 [testenv]
 skip_install = true