upgrade CoroutineWarning to DeprecationWarning

Author: graingert

src/_pytest/warning_types.py

@@ -56,7 +56,7 @@ class PytestRemovedIn8Warning(PytestDeprecationWarning):
 
 
 @final
-class PytestReturnNotNoneWarning(PytestDeprecationWarning):
+class PytestReturnNotNoneWarning(PytestRemovedIn8Warning):
     """Warning emitted when a test function is returning value other than None."""
 
     __module__ = "pytest"
@@ -82,7 +82,7 @@ def simple(cls, apiname: str) -> "PytestExperimentalApiWarning":
 
 
 @final
-class PytestUnhandledCoroutineWarning(PytestWarning):
+class PytestUnhandledCoroutineWarning(PytestRemovedIn8Warning):
     """Warning emitted for an unhandled coroutine.
 
     A coroutine was encountered when collecting test functions, but was not