Error with content type

[lynsei]

Describe the bug
Unsupported manifest media type

makisu build -f Dockerfile -t forktheweb/test-whale:v1.1.0 /mnt

{"level":"info","ts":1569517410.0540462,"msg":"Starting Makisu build (version=v0.1.11-24-g27daadc)"} {"level":"info","ts":1569517410.054741,"msg":"Using build context: /mnt"} {"level":"info","ts":1569517410.054842,"msg":"Using local file at /tmp/makisu-storage/cache_key_value.json for cacheID storage"} {"level":"info","ts":1569517410.0549545,"msg":"No registry information provided, using cached layers"} {"level":"info","ts":1569517410.055083,"msg":"* Stage 1/1 : (alias=0,latestfetched=-1)"} {"level":"info","ts":1569517410.0551178,"msg":"* Step 1/1 (commit) : FROM tutum/hello-world (c13cc9b7)"} {"level":"info","ts":1569517410.0552318,"msg":"* Started pulling image index.docker.io/tutum/hello-world:latest"} {"level":"error","ts":1569517411.0582612,"msg":"failed to execute build plan: execute stage: build stage 0: build node: do execute: execute step: get manifest: pull image index.docker.io/tutum/hello-world:latest: pull manifest: unmarshal distribution manifest: unsupported manifest mediatype: application/vnd.docker.distribution.manifest.v1+prettyjws"}

To Reproduce
Steps to reproduce the behavior:

• Docker version 18.09.7, build 2d0083d
• Installed makisu_build function with the following .zshrc:

function makisu_build() {
    makisu_version=${MAKISU_VERSION:-v0.1.11}
    cd ${@: -1}
    docker run -i --rm --net host \
        -v /var/run/docker.sock:/docker.sock \
        -e DOCKER_HOST=unix:///docker.sock \
        -v $(pwd):/makisu-context \
        -v /tmp/makisu-storage:/makisu-storage \
        gcr.io/makisu-project/makisu:$makisu_version build \
            --commit=explicit \
            --modifyfs=true \
            --load \
            ${@:1:${#@}-1} /makisu-context
    cd -
}

Expected behavior
Build a docker file with simply:

FROM tutum/hello-world

Screenshots
None

Environments
Ubuntu 18.04

Additional context
Add any other context about the problem here--environment configurations, logs, etc.