sysutils/zfs-stats: Update WWW

Since we lost sight of the fact that this port is of a fork, it is no longer
appropriate to use the original (non-fork) URL for WWW purposes.
Instead, use the URL of the fork.

PR:			258238
Approved by:		zirias (mentor), mm (maintainer, timeout)
Differential Revision:	https://reviews.freebsd.org/D42397

sysutils/zfs-stats/Makefile

@@ -4,7 +4,7 @@ CATEGORIES=	sysutils
 
 MAINTAINER=	mm@FreeBSD.org
 COMMENT=	Displays general ZFS information and human-readable statistics
-WWW=		https://www.vx.sk/zfs-stats/
+WWW=		https://github.com/mmatuska/zfs-stats
 
 LICENSE=	BSD2CLAUSE