Cannot build docker image

Hi,
running docker build -t cloud-flow . errors out:
#:~/src/CloudFlow$ git log -1
commit a6f1eb40c74b46a7d9136588325d1d5e95b54099
Author: Guy Shaanan <guy.shaanan@nokia.com>
Date:   Tue Jul 10 11:45:44 2018 +0300

    Fix flexbox size on Firefox
#:~/src/CloudFlow$ git status
On branch master
Your branch is up-to-date with 'origin/master'.
nothing to commit, working directory clean
#:~/src/CloudFlow$ docker build -t cloud-flow .
Sending build context to Docker daemon  1.401MB
Step 1/14 : FROM node:8.9.0 as builder
 ---> 64d053513e64
Step 2/14 : LABEL name="CloudFlow"       version="0.5.0"       description="A workflow visualization tool for OpenStack Mistral"       maintainers="Vitalii Solodilov <mcdkr@yandex.ru>"
 ---> Using cache
 ---> 936c4bfb75d1
Step 3/14 : RUN apt-get update && apt-get install -y apt-transport-https apt-utils &&     curl -sS https://dl.yarnpkg.com/debian/pubkey.gpg | apt-key add - &&     echo "deb https://dl.yarnpkg.com/debian/ stable main" |     tee /etc/apt/sources.list.d/yarn.list &&     apt-get update && apt-get install -y yarn
 ---> Using cache
 ---> ef3e77afa672
Step 4/14 : COPY package.json yarn.lock /build/
 ---> Using cache
 ---> 51fb196dfe0a
Step 5/14 : WORKDIR /build
 ---> Using cache
 ---> e87ef7f484f0
Step 6/14 : RUN yarn install
 ---> Running in 415c01a369b0
yarn install v1.2.1
[1/5] Validating package.json...
error CloudFlow@0.6.3: The engine "yarn" is incompatible with this module. Expected version "^1.3.2".
error Found incompatible module
info Visit https://yarnpkg.com/en/docs/cli/install for documentation about this command.
The command '/bin/sh -c yarn install' returned a non-zero code: 1
Any idea what might trigger this?
Regards Igor
nokia / CloudFlow

Cannot build docker image #39
