Integrate with actions/cache

[simonsan]

run-vcpkg and for example run-cmake as well come with integrated caches. That means by themselves they restore when the action gets called. install-qt-action does it nice as well, it sets again all the important variables after using the cache.

So it would be nice if we could cache msys2 easily or if it caches itself and restores intended behaviour automatically and gets a cached parameter that we can set to true when the cache hits so it knows when to restore the commands/paths etc.