chore: weaviate - lower-bound pin for python-dateutil (#3270)

Author: anakin87

integrations/weaviate/pyproject.toml

@@ -26,7 +26,7 @@ classifiers = [
 dependencies = [
   "haystack-ai>=2.28.0",
   "weaviate-client>=4.20",
-  "python-dateutil",
+  "python-dateutil>=2.7.0",
 ]
 
 [project.urls]