Add postcss-inline-svg (#212)

Lighter 2.x had `postcss-inline-svg`, but in 3.0 it was missing. It broke DDS.

It provides `svg-load` function that inlines SVG into data-uri.

Author: mlajtos

packages/react-scripts/config/webpack.config.js

@@ -185,6 +185,7 @@ module.exports = function(webpackEnv, options = {}) {
               },
               stage: 3,
             }),
+            require('postcss-inline-svg')(),
             // Adds PostCSS Normalize as the reset css with default options,
             // so that it honors browserslist config in package.json
             // which in turn let's users customize the target behavior as per their needs.

packages/react-scripts/package-lock.json

@@ -65,6 +65,7 @@
     "optimize-css-assets-webpack-plugin": "5.0.3",
     "pnp-webpack-plugin": "1.6.0",
     "postcss-flexbugs-fixes": "4.1.0",
+    "postcss-inline-svg": "^4.1.0",
     "postcss-loader": "3.0.0",
     "postcss-normalize": "8.0.1",
     "postcss-preset-env": "6.7.0",