graphics/sdl2_image: enable WEBP by default (needed for games/naev)

graphics/sdl2_image/Makefile

 PORTNAME=	sdl2_image
 DISTVERSIONPREFIX=	release-
 DISTVERSION=	2.6.3
+PORTREVISION=	1
 CATEGORIES=	graphics
 
 MAINTAINER=	amdmi3@FreeBSD.org
@@ -22,7 +23,7 @@ CMAKE_ARGS=	-DSDL2IMAGE_DEBUG_POSTFIX:STRING=
 USE_LDCONFIG=	yes
 
 OPTIONS_DEFINE=	AVIF JPEG JXL PNG TIFF WEBP TEST
-OPTIONS_DEFAULT=AVIF JPEG JXL PNG
+OPTIONS_DEFAULT=AVIF JPEG JXL PNG WEBP
 
 JPEG_USES=		jpeg
 JPEG_CMAKE_BOOL=	SDL2IMAGE_JPG