SDL_mixer: examples/README: these sounds were relicensed as CC-BY-4.0 since obtained.

SDL Commits
1 
From 3a03b79a0de015b2d9ff27205278c953ecef2185 Mon Sep 17 00:00:00 2001
From: "Ryan C. Gordon" <[EMAIL REDACTED]>
Date: Mon, 26 Jan 2026 15:50:34 -0500
Subject: [PATCH] examples/README: these sounds were relicensed as CC-BY-4.0
 since obtained.

Reference Issue #807.
---
 examples/README.md | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/examples/README.md b/examples/README.md
index 0f53860b..7f55abe3 100644
--- a/examples/README.md
+++ b/examples/README.md
@@ -73,10 +73,10 @@ everything consistent. You can ignore it.
   Arcade Music Loop.wav by joshuaempyre ( https://www.empyreanma.com/welcome )
   (We converted this to MP3 format.)
   Original: https://freesound.org/s/251461/
-  License: https://creativecommons.org/licenses/by/3.0/
+  License: https://creativecommons.org/licenses/by/4.0/
 
 - sword.wav:
   sword04.wav by Erdie
   Original: https://freesound.org/s/27858/
-  License: https://creativecommons.org/licenses/by/3.0/
+  License: https://creativecommons.org/licenses/by/4.0/