switch to buildkit builder

Author: alcohol

library/composer

@@ -1,7 +1,8 @@
-# this file was generated using https://github.com/composer/docker/blob/c5d590b6d4400628116c005d025048d09431b5b0/generate-stackbrew-library.sh
+# this file was generated using https://github.com/composer/docker/blob/cc390f2cb76c73a91b7df86d930c2a3b993bc099/generate-stackbrew-library.sh
 
 Maintainers: Composer (@composer), Rob Bast (@alcohol)
 GitRepo: https://github.com/composer/docker.git
+Builder: buildkit
 
 Tags: 2.5.0, 2.5, 2, latest
 Architectures: amd64, arm32v6, arm32v7, arm64v8, i386, ppc64le, s390x