feat: allow custom name for named export

[stefanprobst]

Summary

This adds a namedExport config option to change the named export of the react component, when svgr is used in a loader chain together with something like file-loader. Still defaults to ReactComponent.

Example

// webpack.config.js
module.exports = {
  /* ... */
  module: {
    rules: [
      {
        test: /\.svg$/,
        use: [
          {
            loader: '@svgr/webpack',
            options: {
              namedExport: 'Svg', // defaults to 'ReactComponent'
            },
          },
          { loader: 'file-loader' },
        ],
      },
    ],
  },
}

will allow:

import { Svg as Logo } from 'assets/logo.svg'

Test plan

added tests + docs

[vercel]

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🔍 Inspect: https://vercel.com/gregberge/svgr/dke6a67kx
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[gregberge]

Thanks!