sdl12-compat: Change license file so GitHub UI notices it's zlib.

From 2234721c63cad627aada593006ff2ce3a2eb4438 Mon Sep 17 00:00:00 2001
From: "Ryan C. Gordon" <[EMAIL REDACTED]>
Date: Fri, 26 Feb 2021 14:14:15 -0500
Subject: [PATCH] Change license file so GitHub UI notices it's zlib.

---
 COPYING => LICENSE.txt | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)
 rename COPYING => LICENSE.txt (90%)

diff --git a/COPYING b/LICENSE.txt
similarity index 90%
rename from COPYING
rename to LICENSE.txt
index 9cdb5f8..969b8c1 100644
--- a/COPYING
+++ b/LICENSE.txt
@@ -1,6 +1,4 @@
-
-Simple DirectMedia Layer
-Copyright (C) 1997-2019 Sam Lantinga <slouken@libsdl.org>
+Copyright (C) 1997-2021 Sam Lantinga <slouken@libsdl.org>
   
 This software is provided 'as-is', without any express or implied
 warranty.  In no event will the authors be held liable for any damages