devel/py-pytest4-asyncio: deprecate

After ftp/py-aioftp has switched to up to date pytest, this port
is no longer needed for anything.

Approved by:	portmgr blanket

devel/py-pytest4-asyncio/Makefile

@@ -11,6 +11,9 @@ WWW=		https://pypi.org/project/pytest-asyncio/
 
 LICENSE=	APACHE20
 
+DEPRECATED=	legacy version for pytest4 no longer used by any port
+EXPIRATION_DATA=2022-11-19
+
 CONFLICTS_INSTALL=	${PYTHON_PKGNAMEPREFIX}pytest-asyncio
 
 RUN_DEPENDS=	${PYTHON_PKGNAMEPREFIX}pytest4>=3.0.6:devel/py-pytest4@${PY_FLAVOR}