Change SDL submodule position to release-2.0.20

moralrecordings · moralrecordings · commit 1e53495bf859 · 2022-03-10T20:07:25.000+08:00
diff --git a/sdl2-sys/SDL b/sdl2-sys/SDL
@@ -1 +1 @@
-Subproject commit a1e992b110b9adf3305a5ebb5514f0e970f7911e
+Subproject commit b424665e0899769b200231ba943353a5fee1b6b6
