Upgrades buildx to 0.9.1
v0.9.0 included regressions. Release notes: https://github.com/docker/buildx/releases/tag/v0.9.1
Signed-off-by: Ben Langfeld <blangfeld@powerhrg.com>
(cherry picked from commit 5dcaad0dd33179c16eb2ee1f70429c1884c95bf8)
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>