SDL_image: Check out submodules as needed

SDL Commits
1

https://github.com/libsdl-org/SDL_image/commit/7eb77be12fbec258d201109e57e45f3702e2d03a

From 7eb77be12fbec258d201109e57e45f3702e2d03a Mon Sep 17 00:00:00 2001
From: Sam Lantinga <[EMAIL REDACTED]>
Date: Sat, 7 May 2022 12:35:41 -0700
Subject: [PATCH] Check out submodules as needed

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

diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index f03ff0d..288e583 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -59,6 +59,8 @@ jobs:
           zlib1g-dev \
           ${NULL+}
     - uses: actions/checkout@v2
+      with:
+        submodules: recursive
     - name: Check that versioning is consistent
       # We only need to run this once: arbitrarily use the Linux/CMake build
       if: "runner.os == 'Linux' && matrix.platform.cmake"