Remove upper boundary on supported Python version

This should mean it's possible to install the project on the newly
released Python 3.11.

Author: meshy

CHANGELOG.md

@@ -9,6 +9,7 @@ Version numbers should follow https://semver.org/spec/v2.0.0.html
 
 ### Changed
 
+- Remove upper boundary on supported Python version.
 - Python 3.10 tests now only run against Django 3.2+, because Django <3.2 does
   not support Python 3.10.
 - Specify a minimum `attrs` version of `21.4.0`.

pyproject.toml

@@ -38,7 +38,7 @@ classifiers = [
 
 
 [tool.poetry.dependencies]
-python = ">=3.6,<3.11"
+python = "^3.6"
 attrs = "^21.4.0"
 
 [tool.poetry.dev-dependencies]