refactor: Install & test - CPython 3.7 (ubuntu), codecov.

Author: Ajnus

tests/conftest.py

@@ -514,7 +514,7 @@ def group_dm_template() -> Message:
 
 
 @pytest.fixture(params=["dm_template", "group_dm_template"])
-def direct_message_fixture(request: Any) -> Message:
+def private_message_fixture(request: Any) -> Message:
     return request.getfixturevalue(request.param)