Extract-text-webpack-plugin v1 -> v2

[KevinMind]

Description

When using gatsby-netlify-cms-plugin with gatsby v2 you run into this issue.

Describe the issue that you're seeing.

Error: Cannot find module 'extract-text-webpack-plugin'

• v8-compile-cache.js:159 require
  [kevin-gatsby]/[v8-compile-cache]/v8-compile-cache.js:159:20

• gatsby-node.js:14 Object.
  [kevin-gatsby]/[gatsby-plugin-netlify-cms]/gatsby-node.js:14:25

• v8-compile-cache.js:178 Module._compile
  [kevin-gatsby]/[v8-compile-cache]/v8-compile-cache.js:178:30

• v8-compile-cache.js:159 require
  [kevin-gatsby]/[v8-compile-cache]/v8-compile-cache.js:159:20

• api-runner-node.js:81 runAPI
  [kevin-gatsby]/[gatsby]/dist/utils/api-runner-node.js:81:22

• api-runner-node.js:173 mapSeries
  [kevin-gatsby]/[gatsby]/dist/utils/api-runner-node.js:173:25

• map.js:27
  [kevin-gatsby]/[async]/internal/map.js:27:9

• eachOfLimit.js:66 replenish
  [kevin-gatsby]/[async]/internal/eachOfLimit.js:66:17

Steps to reproduce

git clone https://github.com/KevinMind/gatsby-starter-netlify-cms
cd gatsby-starter-netlify-cms
git checkout gatsby-v2
yarn && yarn develop 

This will throw the error.

Clear steps describing how to reproduce the issue.

Expected result

Potential Cause: I'm not sure if gatsby is using webpack for css processing, but if so, this should be changed for mini-css-extrac-plugin.. I'd be glad to make a PR for this if this is the issue.

[KevinMind]

BTW if you yarn add webpack-extract-text-plugin, the error goes away, so it may not even be used, but is simply required somewhere.. FYI the error goes away if you add it manually.

[m-allanson]

There's an open PR to update the Netlify CMs plugin to work with Gatsby v2: #6056

[sarathy-partha]

need to add extract-text-webpack-plugin (npm or yarn) to get it working....(not webpack-extract-text-plugin)

[erquhart]

Closed in #6356.