feat(setup.py): increase cubicweb max version to 3.31.x

cubicweb_email/__pkginfo__.py

@@ -19,7 +19,7 @@ classifiers = [
     'Programming Language :: JavaScript',
 ]
 __depends__ = {
-    'cubicweb': '>= 3.24',
+    'cubicweb': ">= 3.24, < 3.32.0",
     'cubicweb-file': '>= 1.9.0',
     'cwclientlib': '>= 0.3.1',
 }