text/py-sphinxcontrib-autoprogram: require python 3.7

- Requires python 3.7 [1]

[1] https://github.com/sphinx-contrib/autoprogram/issues/47

PR:		257872
MFH:		2021Q3
(cherry picked from commit 9179bc3865)

textproc/py-sphinxcontrib-autoprogram/Makefile

@@ -1,5 +1,6 @@
 PORTNAME=	sphinxcontrib-autoprogram
 PORTVERSION=	0.1.7
+PORTREVISION=	1
 CATEGORIES=	textproc
 MASTER_SITES=	CHEESESHOP
 PKGNAMEPREFIX=	${PYTHON_PKGNAMEPREFIX}
@@ -12,7 +13,7 @@ LICENSE=	BSD2CLAUSE
 RUN_DEPENDS=	${PYTHON_PKGNAMEPREFIX}six>0:devel/py-six@${PY_FLAVOR} \
 		${PYTHON_PKGNAMEPREFIX}sphinx>=1.2,1:textproc/py-sphinx@${PY_FLAVOR}
 
-USES=		python
+USES=		python:3.7+
 USE_PYTHON=	autoplist concurrent distutils
 
 NO_ARCH=	yes