SDL_image: upgrade vendored libpng from 1.6.45 to 1.6.46 (f0968)

From f0968c09c24c08dd00685d923c9c32ee2ca30832 Mon Sep 17 00:00:00 2001
From: Ozkan Sezer <[EMAIL REDACTED]>
Date: Mon, 27 Jan 2025 20:33:02 +0300
Subject: [PATCH] upgrade vendored libpng from 1.6.45 to 1.6.46

(cherry picked from commit dc73d46521daa0edaa55f67dc3164680e0610356)
---
 .gitmodules     | 2 +-
 external/libpng | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/.gitmodules b/.gitmodules
index 35260435..194b6afc 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -5,7 +5,7 @@
 [submodule "external/libpng"]
 	path = external/libpng
 	url = https://github.com/libsdl-org/libpng.git
-	branch = v1.6.45-SDL
+	branch = v1.6.46-SDL
 [submodule "external/libwebp"]
 	path = external/libwebp
 	url = https://github.com/libsdl-org/libwebp.git
diff --git a/external/libpng b/external/libpng
index 68ff096f..f98df89f 160000
--- a/external/libpng
+++ b/external/libpng
@@ -1 +1 @@
-Subproject commit 68ff096f781a935233cbe7972bd5fc45f586b948
+Subproject commit f98df89f110248450c1552e69c6346b1c901a453