Update terser-webpack-plugin

[pustovalov]

terser-webpack-plugin

https://github.com/webpack-contrib/terser-webpack-plugin/blob/master/CHANGELOG.md

4.0.0 (2020-08-04)

⚠ BREAKING CHANGES

• the warningsFilter option was remove without replacement,
• terser version is 5,
• returned value of the minify option was changes, only code/map/extractedComments are valid

Features

• improved compatibility with webpack@5

terser

https://github.com/terser/terser/blob/master/CHANGELOG.md

v5.0.0

• in operator now taken into account during property mangle.
• Fixed infinite loop in face of a reference loop in some situations.
• Kept exports and imports around even if there's something which will throw before them.
• The main exported bundle for commonjs, dist/bundle.min.js is no longer minified.

v5.0.0-beta.0

• BREAKING: minify() is now async and rejects a promise instead of returning an error.
• BREAKING: Internal AST is no longer exposed, so that it can be improved without releasing breaking changes.
• BREAKING: Lowest supported node version is 10
• Module is now distributed as a dual package - You can import and require() too.
• Inline improvements were made