use npm install and let travis do the switch?

.travis.yml

@@ -7,7 +7,7 @@ install:
 - pip install --upgrade pip
 - pip install pipenv
 - pipenv install --dev
-- npm ci # use package-lock.json
+- npm install # use package-lock.json
 - pipenv run python network-api/manage.py collectstatic --no-input
 before_script:
 - psql -c 'create database network;' -U postgres