- Automatically start a buildkit daemon if no BUILDKIT_HOST is
provided (and if not already started)
- Customization of BUILDKIT_HOST is still possible, just like before
- Automatically upgrade the managed daemon to the version used by dagger
if necessary
- Add CI test to make sure the managed buildkit and the vendored
buildkit versions match
Signed-off-by: Andrea Luzzardi <aluzzardi@gmail.com>
