fix: use tomli for Python 3.10 compatibility in tests

tomllib is only available in Python 3.11+, so we need to use tomli
as a fallback for Python 3.10.

Co-Authored-By: João <joao@crewai.com>

lib/crewai/tests/test_dependency_constraints.py

@@ -1,8 +1,13 @@
 """Test that dependency constraints are compatible with common integrations."""
 
-import tomllib
+import sys
 from pathlib import Path
 
+if sys.version_info >= (3, 11):
+    import tomllib
+else:
+    import tomli as tomllib
+
 from packaging.specifiers import SpecifierSet
 from packaging.version import Version