Remove upper bound on python requirement

Remove the restriction that python must not be newer than the latest
version since this seems to make using constriction with poetry slightly
more difficult.

pyproject.toml

@@ -21,7 +21,7 @@ maintainers = [
 ]
 name = "constriction"
 readme = "README-python.md"
-requires-python = ">=3.7,<3.13"
+requires-python = ">=3.7"
 
 [project.urls]
 changelog = "https://github.com/bamler-lab/constriction/releases"