Pass additional assetInfo object when calling emitFile

[bschlenk]

• Operating System: MacOS
• Node Version: 12.6.1
• NPM Version: 6.14.7
• webpack Version: 4.29.6
• file-loader Version: 3.0.1

Feature Proposal

Webpack loader's emitFile call takes a 4th param that can provide additional info about an asset, like whether it is immutable or not. file-loader should pass in { immutable: true } when the file name includes [contenthash] so that other plugins can benefit from this info.

The new assetInfo param was added in webpack/webpack#9038.

Feature Use Case

I'm writing a plugin that uses this info to determine what cache-control headers a file can be given.

[alexander-akait]

Let's do it

[alexander-akait]

Fixed by #383