sdl12-compat: CI: switch to SDL2 release-2.0.18

From 47e1fe0962e47f3caca88b240e4c48efb1cb220e Mon Sep 17 00:00:00 2001
From: Ozkan Sezer <[EMAIL REDACTED]>
Date: Wed, 8 Dec 2021 12:25:20 +0300
Subject: [PATCH] CI: switch to SDL2 release-2.0.18

---
 .github/workflows/main.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index f46387b..1552ec6 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -24,7 +24,7 @@ jobs:
       uses: actions/checkout@v2
       with:
         repository: libsdl-org/SDL
-        ref: release-2.0.14
+        ref: release-2.0.18
         path: SDL2
     - name: Configure CMake
       run: cmake -DSDL2_INCLUDE_DIR="${{ github.workspace }}/SDL2/include" -B build ${{ matrix.platform.flags }}