20f5f536dc
Closes #482 I traced the problem to where buildx parses the cli args ([here](https://github.com/docker/buildx/blob/fa4461b9a1ec45c23d1b9e32dee0d0a8ed29900b/util/buildflags/cache.go#L14)), and confirmed it applies defaults based on GHA environment variables and ignores the cacheTo/cacheFrom directive altogether when the variables aren't available. The fix is to ignore the GHA cache directive when it the upstream parser ignores it.