chore: Move css-loader and others into devDependencies by hborchardt · Pull Request #7407 · plotly/plotly.js

Fixes #7430.

Some recent PRs (#7142, #7140) introduced the css-loader, style-loader and esbuild-style-plugin as dependencies. However it seems that they should be categorized as devDependencies instead, because they don't end up in the bundle, but are used to create the bundle.

This poses a problem for me, as it causes npm install plotly.js to install significantly more dependencies than necessary.

In order to not install css-loader and its dependencies during a npm install plotly.js, turn them into devDependencies.