[DO NOT MERGE] Make appveyor use the correct dependencies versions.

appveyor/install_kiwix-desktop.cmd

@@ -2,6 +2,7 @@ REM ========================================================
 REM Install kiwix-desktop
 git clone https://github.com/kiwix/kiwix-desktop || exit /b 1
 cd kiwix-desktop
+git checkout 2.3.1 || exit /b 1
 echo "Running qmake"
 SET _WITH_CONSOLE=1
 IF %KIWIX_DESKTOP_RELEASE% EQU 1 (

appveyor/install_libkiwix.cmd

@@ -2,6 +2,7 @@ REM ========================================================
 REM Install libkiwix
 git clone https://github.com/kiwix/libkiwix.git || exit /b 1
 cd libkiwix
+git checkout 12.0.0 || exit /b 1
 set CPPFLAGS="-I%EXTRA_DIR%/include"
 meson . build --prefix %EXTRA_DIR% --default-library static --buildtype release || exit /b 1
 cd build

appveyor/install_libzim.cmd

@@ -2,6 +2,7 @@ REM ========================================================
 REM Install libzim
 git clone https://github.com/openzim/libzim.git || exit /b 1
 cd libzim
+git checkout 8.1.0 || exit /b 1
 meson . build --prefix %EXTRA_DIR% --default-library static --buildtype release || exit /b 1
 cd build
 ninja || exit /b 1