Upgrade dependencies & raise minimum Node.js version

[realityking]

I've made several upgrades to madge related dependencies in the last few months. The result should be that madge is better aligned with the behaviour of other project and allow deduplication with their dependencies.

Here are some highlights though likely incomplete:

• PostCSS 8 (Use PostCSS 8 and require Node.js 10 dependents/node-detective-postcss#76)
• Smaller dependencies for module-lookup-amd (Require Node.js 10 + simplify dependencies dependents/node-module-lookup-amd#29)
• Remove dependency on make-dir (Require Node.js 10 and remove the dependency on make-dir webforge-labs/requirejs-config-file#12)
• enhanced-resolve v5 - matching Webpack 5 - with support for exports in package.json (Require Node.js 10.13 and upgrade most dependencies dependents/node-filing-cabinet#94)
• @typescript-eslint/typescript-estree v4 (Require Node.js 10 and upgrade @typescript-eslint/typescript-estree dependents/detective-typescript#30)

[pahen]

Awesome job! I'll merge and create a new major release of Madge since it contains some breaking changes.