webpackでライブラリのライセンス表記を漏れなく出力する方法

webpackのchunkで出力される外部ライブラリのライセンス表記を確認したところ、
pixi.jsなどの一部のライブラリのライセンス表記が出力されません。

uglifyjs-webpack-pluginやterser-webpack-pluginを使用してみたのですが、記述が正しくない為かうまくいきません。どのように対処したらよいのでしょうか。

json
1・tsconfig.json
2{
3  "compilerOptions": {
4    "target": "es3",
5    "module": "CommonJS",
6    "lib": ["dom", "esnext"],
7    "baseUrl": "./src/ts",
8    "outDir": "./dist/js",
9    "sourceMap": false,
10    "allowJs": true,
11    "alwaysStrict": true,
12    "esModuleInterop": true,
13    "forceConsistentCasingInFileNames": true,
14    "isolatedModules": true,
15    "moduleResolution": "node",
16    "noEmit": false,
17    "noFallthroughCasesInSwitch": true,
18    "noUnusedLocals": false,
19    "noUnusedParameters": false,
20    "removeComments": true,
21    "skipLibCheck": true,
22    "strict": true,
23    "noImplicitAny": false,
24    "strictNullChecks": false
25  },
26  "compileOnSave": true,
27  "include": [
28    "src/ts/**/*.ts"
29  ],
30  "exclude": [
31    "node_modules",
32  ],
33}

js
1・webpack.common.js
2const path = require("path");
3const TerserPlugin = require('terser-webpack-plugin');
4const OptimizeCssAssetsPlugin = require("optimize-css-assets-webpack-plugin");
5const UglifyJsPlugin = require('uglifyjs-webpack-plugin');
6module.exports = {
7  entry: {
8    app: "./src/ts/index.ts"
9  },
10  output: {
11    filename: "js/[name].js",
12    chunkFilename: "js/vendor.js",
13    path: path.join(__dirname, "dist")
14  },
15  module: {
16    rules: [{
17        test: /.ts$/,
18        use: "ts-loader",
19        exclude: /node_modules/
20      }
21    ]
22  },
23  optimization: {
24    minimize: true,
25    minimizer: [
26      new UglifyJsPlugin({
27        uglifyOptions: {
28          output: {
29            comments: /^!/,
30          }
31        }
32      }),
33      // new TerserPlugin({
34      //   extractComments: /^**!|@preserve|@license|@cc_on/i,
35      // }),
36      new OptimizeCssAssetsPlugin({})
37    ],
38    splitChunks: {
39      cacheGroups: {
40        vendor: {
41          test: /node_modules/,
42          name: "vendor",
43          chunks: "initial",
44          enforce: true
45        }
46      }
47    }
48  },
49  resolve: {
50    extensions: [".ts", ".js"]
51  }
52};

js
1・webpack.prod.js
2
3const merge = require('webpack-merge');
4const common = require('./webpack.common.js');
5module.exports = merge(common, {
6  mode: "production",
7  devtool: false,
8});

js
1・webpack.dev.js
2
3const merge = require('webpack-merge');
4const common = require('./webpack.common.js');
5const path = require("path");
6module.exports = merge(common, {
7  mode: "development",
8  devServer: {
9    watchContentBase: true,
10    disableHostCheck: true,
11    contentBase: path.join(__dirname, "src"),
12    compress: true,
13    port: 8080,
14    open: true
15  },
16  devtool: 'source-map',
17});

json
1・package.json
2{
3  "name": "sample",
4  "version": "1.0.0",
5  "description": "",
6  "main": "index.js",
7  "scripts": {
8    "test": "echo \"Error: no test specified\" && exit 1",
9    "build": "webpack --config webpack.prod.js",
10    "dev": "webpack-dev-server --config webpack.dev.js"
11  },
12  "author": "",
13  "license": "ISC",
14  "devDependencies": {
15    "@babel/core": "^7.6.2",
16    "@babel/preset-env": "^7.6.2",
17    "@types/gsap": "^1.20.2",
18    "@types/jest": "^25.1.3",
19    "@types/jquery": "^3.3.35",
20    "@types/pixi.js": "^4.8.7",
21    "babel-core": "^7.0.0-bridge.0",
22    "babel-jest": "^24.9.0",
23    "babel-loader": "^8.0.6",
24    "babel-preset-env": "^1.7.0",
25    "jest": "^24.9.0",
26    "jest-useragent-mock": "0.0.3",
27    "mini-css-extract-plugin": "^0.9.0",
28    "optimize-css-assets-webpack-plugin": "^5.0.3",
29    "terser-webpack-plugin": "^2.3.6",
30    "ts-jest": "^25.2.1",
31    "ts-loader": "^6.2.2",
32    "typescript": "^3.8.3",
33    "uglifyjs-webpack-plugin": "^2.2.0",
34    "webpack": "^4.42.1",
35    "webpack-cli": "^3.3.11",
36    "webpack-dev-server": "^3.10.3",
37    "webpack-merge": "^4.2.2"
38  },
39  "dependencies": {
40    "gsap": "^3.2.0",
41    "jquery": "^3.5.0",
42    "pixi.js": "^4.8.7",
43  }
44}