graphics/py-imageio: Update to 2.18.0

Changes:	https://github.com/imageio/imageio/releases

graphics/py-imageio/Makefile

 PORTNAME=	imageio
-PORTVERSION=	2.17.0
+PORTVERSION=	2.18.0
 CATEGORIES=	graphics python
 MASTER_SITES=	CHEESESHOP
 PKGNAMEPREFIX=	${PYTHON_PKGNAMEPREFIX}

graphics/py-imageio/distinfo

-TIMESTAMP = 1650970141
-SHA256 (imageio-2.17.0.tar.gz) = b21f009e52eb22b02b839f3bf2ae5374aaf0886317313c1358c6014e5383b539
-SIZE (imageio-2.17.0.tar.gz) = 3422328
+TIMESTAMP = 1651316645
+SHA256 (imageio-2.18.0.tar.gz) = 090898c48532631ab11c74ae743e64c24dabda45c16db46f7e3bec9e2d8f422f
+SIZE (imageio-2.18.0.tar.gz) = 3422462