[Feature Request]: builtins.css.modules support auto config

[hzura]

What problem does this feature solve?

Currently, if you need to support both .less and .module.less files in the project, you need to configure their types separately like below. (plz forgive me if I have used them incorrectly)

{
  test: /\.less$/,
  use: [{
	  loader: 'less-loader',
  }],
  type: 'css/module',
},
{
  test: /^(.(?!\.module))+\.less$/,
  use: [{
	  loader: 'less-loader',
  },],
  type: 'css',
},

I hope that builtins.css.modules config can support option auto like css-loader, allowing automatic differentiation using regular expressions (as the cost of using a function may be high at the moment)
preference: https://webpack.js.org/loaders/css-loader/#modules

What does the proposed API of configuration look like?

type BuiltinsCssModules = {
  localsConvention?:
    | 'asIs'
    | 'camelCase'
    | 'camelCaseOnly'
    | 'dashes'
    | 'dashesOnly';
  localIdentName?: string;
  exportsOnly?: boolean;
  auto?: boolean | RegExp;
};

[hardfist]

waiting for webpack/webpack#16572 resolved

[evertzz]

I wonder how to support module.less, the configuration above does't work

[hardfist]

since webpack/webpack#16577 landed, we can continue supporting it now