Enable pytest failures on warnings from cudf (#5796)

The test suite will now fail when a warning comes from cudf as apart of rapidsai/build-planning#26.

Authors:
  - Matthew Roeschke (https://github.com/mroeschke)

Approvers:
  - Dante Gama Dessavre (https://github.com/dantegd)

URL: #5796

python/pyproject.toml

@@ -39,6 +39,7 @@ testpaths = "cuml/tests"
 
 filterwarnings = [
   "error::FutureWarning:cuml[.*]", # Catch uses of deprecated positional args in testing
+  "error:::cudf",
   "ignore:[^.]*ABCs[^.]*:DeprecationWarning:patsy[.*]",
   "ignore:(.*)alias(.*):DeprecationWarning:hdbscan[.*]",
 ]