Support Webpack 5

This plugin doesn’t work with Webpack 5. Here’s a minimal example of how it fails:

[user@academic:~/favicons-webpack-plugin-webpack-5-example]% cat webpack.config.js 
const HtmlPlugin = require('html-webpack-plugin');
const FaviconsPlugin = require('favicons-webpack-plugin');

module.exports = {
	plugins: [
		new HtmlPlugin(),
		new FaviconsPlugin(),
	],
};
[user@academic:~/favicons-webpack-plugin-webpack-5-example]% cat package.json 
{
  "name": "favicons-webpack-plugin-webpack-5-example",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "",
  "license": "ISC",
  "devDependencies": {
    "favicons-webpack-plugin": "^4.2.0",
    "html-webpack-plugin": "^4.3.0",
    "webpack": "^5.0.0-beta.28",
    "webpack-cli": "^3.3.12"
  }
}
[user@academic:~/favicons-webpack-plugin-webpack-5-example]% npx webpack                   
(node:372532) [DEP_WEBPACK_MAIN_TEMPLATE_GET_ASSET_PATH] DeprecationWarning: MainTemplate.getAssetPath is deprecated (use Compilation.getAssetPath instead)
(Use `node --trace-deprecation ...` to show where the warning was created)
(node:372532) [DEP_WEBPACK_TEMPLATE_PATH_PLUGIN_REPLACE_PATH_VARIABLES_HASH] DeprecationWarning: [hash] is now [fullhash] (also consider using [chunkhash] or [contenthash], see documentation for details)
(node:372532) UnhandledPromiseRejectionWarning: TypeError: Cannot read property 'assets' of undefined
    at /home/user/favicons-webpack-plugin-webpack-5-example/node_modules/favicons-webpack-plugin/src/compiler.js:69:47
    at /home/user/favicons-webpack-plugin-webpack-5-example/node_modules/webpack/lib/Compiler.js:486:11
    at /home/user/favicons-webpack-plugin-webpack-5-example/node_modules/webpack/lib/Compiler.js:981:17
    at eval (eval at create (/home/user/favicons-webpack-plugin-webpack-5-example/node_modules/tapable/lib/HookCodeFactory.js:33:10), <anonymous>:13:1)
    at processTicksAndRejections (internal/process/task_queues.js:93:5)
(node:372532) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag `--unhandled-rejections=strict` (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode). (rejection id: 1)
(node:372532) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.
[user@academic:~/favicons-webpack-plugin-webpack-5-example]% node --no-deprecation node_modules/.bin/webpack
(node:373112) UnhandledPromiseRejectionWarning: TypeError: Cannot read property 'assets' of undefined
    at /home/user/favicons-webpack-plugin-webpack-5-example/node_modules/favicons-webpack-plugin/src/compiler.js:69:47
    at /home/user/favicons-webpack-plugin-webpack-5-example/node_modules/webpack/lib/Compiler.js:486:11
    at /home/user/favicons-webpack-plugin-webpack-5-example/node_modules/webpack/lib/Compiler.js:981:17
    at eval (eval at create (/home/user/favicons-webpack-plugin-webpack-5-example/node_modules/tapable/lib/HookCodeFactory.js:33:10), <anonymous>:13:1)
    at processTicksAndRejections (internal/process/task_queues.js:93:5)
(Use `node --trace-warnings ...` to show where the warning was created)
(node:373112) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag `--unhandled-rejections=strict` (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode). (rejection id: 1)
[user@academic:~/favicons-webpack-plugin-webpack-5-example]% 

[smorimoto]

5 has already been released and it seems to make a lot of sense to complete this.

[jantimon]

Tests passed: https://travis-ci.org/github/jantimon/favicons-webpack-plugin/builds/739620669 Released as favicons-webpack-plugin@5.0.0-alpha.1: https://www.npmjs.com/package/favicons-webpack-plugin/v/5.0.0-alpha.1