CI/Flatpak: Switch from JSON -> YAML

Actually lets me have comments...

scripts/flatpak/modules/20-sdl2.yaml

@@ -0,0 +1,23 @@
+name: sdl2
+buildsystem: cmake-ninja
+builddir: true
+config-opts:
+  - "-DCMAKE_BUILD_TYPE=Release"
+  - "-DBUILD_SHARED_LIBS=ON"
+  - "-DSDL_SHARED=ON"
+  - "-DSDL_STATIC=OFF"
+  - "-DSDL_TESTS=OFF"
+build-options:
+  strip: true
+sources:
+  - type: archive
+    url: "https://github.com/libsdl-org/SDL/releases/download/release-2.30.6/SDL2-2.30.6.tar.gz"
+    sha256: "c6ef64ca18a19d13df6eb22df9aff19fb0db65610a74cc81dae33a82235cacd4"
+cleanup:
+  - /bin
+  - /include
+  - /lib/*.a
+  - /lib/*.la
+  - /lib/cmake
+  - /lib/pkgconfig
+  - /share/aclocal