build-emux-docker fails to `apk update` with permission denied

[ethanwilloner]

./build-emux-docker
...
ERROR [ 2/39] RUN apk update 0.4s

[ 2/39] RUN apk update:
#5 0.247 ERROR: Unable to lock database: Permission denied
#5 0.250 ERROR: Failed to open apk database: Permission denied

executor failed running [/bin/sh -c apk update]: exit code: 99

After poking around the build script, I found that removing DOCKER_BUILDKIT=1 from the docker build command fixed the issues. This was found on up to date Fedora 35 running podman.