cad/openvsp: update to 3.39.1

- Fix 3D background relative path bug (Windows)

cad/openvsp/Makefile

 PORTNAME=	openvsp
 DISTVERSIONPREFIX=	${GH_PROJECT}_
-DISTVERSION=	3.39.0
+DISTVERSION=	3.39.1
 CATEGORIES=	cad
 
 MAINTAINER=	fernape@FreeBSD.org

cad/openvsp/distinfo

-TIMESTAMP = 1715581261
-SHA256 (OpenVSP-OpenVSP-OpenVSP_3.39.0_GH0.tar.gz) = b2b2d258a03cfe47e8e7d145be320c90f0e14e4b1d115162895c27f70918a018
-SIZE (OpenVSP-OpenVSP-OpenVSP_3.39.0_GH0.tar.gz) = 125467960
+TIMESTAMP = 1715767081
+SHA256 (OpenVSP-OpenVSP-OpenVSP_3.39.1_GH0.tar.gz) = ba42e2bad11f086787fb06eee2300c8a2a106d410791508447a380131e576fb2
+SIZE (OpenVSP-OpenVSP-OpenVSP_3.39.1_GH0.tar.gz) = 125467558