build: add missing license-webpack-plugin dev dependency

Author: alan-agius4

package.json

@@ -176,6 +176,7 @@
     "less": "4.1.1",
     "less-loader": "9.0.0",
     "license-checker": "^25.0.0",
+    "license-webpack-plugin": "2.3.19",
     "loader-utils": "2.0.0",
     "magic-string": "0.25.7",
     "mini-css-extract-plugin": "1.6.0",