At the moment vendor.conf is missing entries for `github.com/tonistiigi/llb-gobuild`
and `github.com/morikuni/aec` due in part because of a combination of
https://github.com/LK4D4/vndr/issues/62 and https://github.com/LK4D4/vndr/issues/63.
The issue vndr#63 (related to lack of `github.com/morikuni/aec`) can be worked
around by removing the vendor directory before rerunning `vndr`, so do so.
Due to vndr#62 the issue with `github.com/tonistiigi/llb-gobuild` cannot be
detected at the moment, but pass `-strict` to `vndr` in anticipation of a fix
there.
Signed-off-by: Ian Campbell <ijc@docker.com>