Freeze MLT version for packaging

packaging/appimage/3rdparty/ext_mlt/CMakeLists.txt

@@ -2,8 +2,9 @@ ExternalProject_Add(
   ext_mlt
   DOWNLOAD_DIR ${EXT_DOWNLOAD_DIR}
   GIT_REPOSITORY https://github.com/mltframework/mlt.git
+  GIT_TAG v6.26.1
 
-  CONFIGURE_COMMAND <SOURCE_DIR>/configure --prefix=${EXT_INSTALL_DIR} ${AT_HOST} ${AT_SHARED_ONLY} --enable-gpl --enable-gpl3 --enable-opencv --enable-opengl --enable-lumas --avformat-swscale
+  CONFIGURE_COMMAND <SOURCE_DIR>/configure --prefix=${EXT_INSTALL_DIR} ${AT_HOST} ${AT_SHARED_ONLY} --enable-gpl --enable-gpl3 --enable-opencv --enable-opengl
   BUILD_IN_SOURCE 1
   BUILD_ALWAYS TRUE
   BUILD_COMMAND $(MAKE) clean

packaging/flatpak/org.kde.kdenlive-nightly.json

@@ -565,7 +565,8 @@
         {
           "type": "git",
           "url": "https://github.com/mltframework/mlt.git",
-          "branch": "master"
+          "commit": "531aa1a19df55cc378c9c79b86c7cbb187487f37",
+          "tag": "v6.26.1"
         }
       ]
     },