docs: fix externalsPreset docs

Add `target: 'node'` even when using `externalsPreset`

Author: liady

README.md

@@ -29,14 +29,15 @@ module.exports = {
 ```
 And that's it. All node modules will no longer be bundled but will be left as `require('module')`.
 
-**Note**: For Webpack 5, replace `target: 'node'` with the `externalsPreset` object:
+**Note**: For Webpack 5, in addition to `target: 'node'` also include the `externalsPreset` object:
 ```js
 // Webpack 5
 
 const nodeExternals = require('webpack-node-externals');
 ...
 module.exports = {
     ...
+    target: 'node', 
     externalsPresets: { node: true }, // in order to ignore built-in modules like path, fs, etc.
     externals: [nodeExternals()], // in order to ignore all modules in node_modules folder
     ...