Add mpv module to Flatpak manifest

dev.bscubed.Luminate.json

@@ -33,6 +33,27 @@
     "*.a"
   ],
   "modules": [
+    {
+      "name": "mpv",
+      "buildsystem": "meson",
+      "config-opts": [
+        "-Dlibmpv=true",
+        "-Dcplayer=false",
+        "-Dlua=disabled",
+        "-Djavascript=disabled",
+        "-Duchardet=disabled",
+        "-Drubberband=disabled",
+        "-Dvapoursynth=disabled",
+        "-Dmanpage-build=disabled"
+      ],
+      "sources": [
+        {
+          "type": "archive",
+          "url": "https://github.com/mpv-player/mpv/archive/v0.39.0.tar.gz",
+          "sha256": "replace-with-actual-sha256"
+        }
+      ]
+    },
     {
       "name": "Luminate",
       "builddir": true,