[WIP] Add correct `devtool` key to webpack dev config
[WIP] Add correct `devtool` key to webpack dev config

netlify/netlify-cms,dopry/netlify-cms,netlify/netlify-cms,Aloomaio/netlify-cms,dopry/netlify-cms,Aloomaio/netlify-cms,netlify/netlify-cms,netlify/netlify-cms