transform only editor.main.js

BREAKING CHANGES:
if a project contains only these imports for creating editor:
```
import * as monaco from 'monaco-editor/esm/vs/editor/editor.api.js';
const editor = monaco.editor.create(...);
```
`monaco-editor-webpack-plugin` will not add features and languages. When creating editor,
 monaco must be imported from package itself:
 ```
 import * as monaco from 'monaco-editor';
 const editor = monaco.editor.create(...);
 ```

Author: ValeraS

webpack-plugin/src/index.ts

@@ -313,7 +313,7 @@ function createLoaderRules(
 	};
 	return [
 		{
-			test: /esm[/\\]vs[/\\]editor[/\\]editor.(api|main).js/,
+			test: /esm[/\\]vs[/\\]editor[/\\]editor.main.js/,
 			use: [
 				{
 					loader: INCLUDE_LOADER_PATH,