Install 32 bit OpenGL libraries explicitly in the CI workflow

For some reason 32 bit libgl1 is not pulled in as win32 dependency any
more, resulting in errors when running the test using Direct2D.

Fix this by installing the package explicitly.

.github/workflows/ci_msw_cross.yml

@@ -106,7 +106,7 @@ jobs:
             i686-w64-mingw32)
               sudo dpkg --add-architecture i386
               sudo apt-get -q -o=Dpkg::Use-Pty=0 update
-              packages="$packages g++-mingw-w64-i686 wine32"
+              packages="$packages g++-mingw-w64-i686 wine32 libgl1:i386"
               winerun=wine
               ;;