test: fix assertion error in timestamp_to_date invalid test

tests/test_datetime.py

@@ -16,7 +16,11 @@ def test_correct() -> None:
 
 def test_invalid() -> None:
     """Test timestamp_to_date() with an invalid timestamp."""
+    allowed_errors: list[str] = [
+        "'str' object cannot be interpreted as an integer",
+        "argument must be int or float, not str"
+    ]
     timestamp: str = "hello"
     with pytest.raises(TypeError) as excinfo:
         timestamp_to_date(timestamp)
-    assert "'str' object cannot be interpreted as an integer" in str(excinfo.value)
+    assert str(excinfo.value) in allowed_errors