migrates to webpack 4 to enforce security (#818)

Signed-off-by: Denis barbaron <denis.barbaron@orange.com>

lib/units/app/middleware/webpack.js

@@ -1,3 +1,7 @@
+//
+// Copyright © 2024 contains code contributed by Orange SA, authors: Denis Barbaron - Licensed under the Apache license 2.0
+//
+
 var path = require('path')
 var url = require('url')
 
@@ -69,9 +73,9 @@ module.exports = function(localOptions) {
     }
   }
 
-  compiler.plugin('done', doneListener)
-  compiler.plugin('invalid', invalidate)
-  compiler.plugin('compile', invalidate)
+  compiler.hooks.done.tap('done', doneListener)
+  compiler.hooks.invalid.tap('invalid', invalidate)
+  compiler.hooks.compile.tap('compile', invalidate)
 
   function bundle() {
     if (valid) {