devel/py-awscrt: Update to 0.16.18

Changes:	https://github.com/awslabs/aws-crt-python/releases

devel/py-awscrt/Makefile

 PORTNAME=	awscrt
-PORTVERSION=	0.16.17
+PORTVERSION=	0.16.18
 CATEGORIES=	devel python
 MASTER_SITES=	PYPI
 PKGNAMEPREFIX=	${PYTHON_PKGNAMEPREFIX}

devel/py-awscrt/distinfo

-TIMESTAMP = 1683478900
-SHA256 (awscrt-0.16.17.tar.gz) = 9a7220fd677a8fc2642fb360d9b557fb0fb3b71c2e2712700e567bc2b89b4f55
-SIZE (awscrt-0.16.17.tar.gz) = 28320725
+TIMESTAMP = 1685162108
+SHA256 (awscrt-0.16.18.tar.gz) = d29cbfabd10cebc98609f7a7757e45795ad8aaa31ba47870a7950b68f2a5c281
+SIZE (awscrt-0.16.18.tar.gz) = 28486531