graphics/mtpaint: update to 3.50.09

- use DISTVERSION instead of PORTVERSION

Changelog-like descriptions in each commit since 3.50.3 [1].

[1] https://github.com/wjaguar/mtPaint/commits/master

Approved by:	dbaio, garga (mentors)
Differential Revision:	https://reviews.freebsd.org/D30034

graphics/mtpaint/Makefile

 # Created by: Andrew Pantyukhin <infofarmer@FreeBSD.org>
 
 PORTNAME=	mtpaint
-PORTVERSION=	3.50.08
+DISTVERSION=	3.50.09
 CATEGORIES=	graphics
 
 MAINTAINER=	eduardo@FreeBSD.org

graphics/mtpaint/distinfo

-TIMESTAMP = 1616051072
-SHA256 (wjaguar-mtPaint-3.50.08-4ea607e_GH0.tar.gz) = 015a76531d4f6e2cd2742b021dd25ed0240af4ab4dc7f33e190c52f739f63317
-SIZE (wjaguar-mtPaint-3.50.08-4ea607e_GH0.tar.gz) = 1204999
+TIMESTAMP = 1619246701
+SHA256 (wjaguar-mtPaint-3.50.09-4ea607e_GH0.tar.gz) = 015a76531d4f6e2cd2742b021dd25ed0240af4ab4dc7f33e190c52f739f63317
+SIZE (wjaguar-mtPaint-3.50.09-4ea607e_GH0.tar.gz) = 1204999