Cap cattrs<25.1 (#180)

Broken by this commit:

> Potentially breaking: The converters raise StructureHandlerNotFoundError more
> eagerly (on hook creation, instead of on hook use). This helps surfacing
> problems with missing hooks sooner.
> (python-attrs/cattrs#577)

https://catt.rs/en/stable/history.html#id2

Author: hoodmane

setup.py

@@ -20,7 +20,7 @@
         "Sphinx>=4.1.0",
         "markupsafe==3.0.2",
         "attrs",
-        "cattrs",
+        "cattrs<25.1",
     ],
     python_requires=">=3.10",
     classifiers=[