pytest.ini: Silent annoying warning

Pytest report when building debian package is not easily exploitable without silenting that warning.

pytest.ini: Silent annoying warning
a65bc357 · Antoine Lambert · 2a35b545 · a65bc357
Commit a65bc357 authored 4 years ago by Antoine Lambert
--- a/pytest.ini
+++ b/pytest.ini
@@ -8,3 +8,4 @@ filterwarnings =
    ignore:.*uses the 'client' fixture
    ignore:.*uses the 'mocker' fixture
    ignore:.*uses the 'requests_mock' fixture
+    ignore:.*'U' mode is deprecated