Update to 0.8.0

Changes:	https://github.com/theskumar/python-dotenv/blob/master/README.rst#changelog

www/py-python-dotenv/Makefile

@@ -2,7 +2,7 @@
 # $FreeBSD$
 
 PORTNAME=	python-dotenv
-PORTVERSION=	0.7.1
+PORTVERSION=	0.8.0
 CATEGORIES=	www python
 MASTER_SITES=	CHEESESHOP
 PKGNAMEPREFIX=	${PYTHON_PKGNAMEPREFIX}

www/py-python-dotenv/distinfo

-TIMESTAMP = 1516901147
-SHA256 (python-dotenv-0.7.1.tar.gz) = 45e927c34204c90f5faa35ea8709b894f6b1a7712d77eb50940601068040993b
-SIZE (python-dotenv-0.7.1.tar.gz) = 10611
+TIMESTAMP = 1520176912
+SHA256 (python-dotenv-0.8.0.tar.gz) = 2bfeb2ce1b5d1ce46ecdce5c9d55e4976ca403fdcc251b4870e5c0647d0dce67
+SIZE (python-dotenv-0.8.0.tar.gz) = 15912