check-dependencies

Notable non-breaking changes:

• support npm package aliases (#50)
• reduced a number of external dependencies
• npm prune is no longer called asnpm install already prunes

Breaking changes:

• dropped the callback interface - use promises instead
• dropped the checkCustomPackageNames option
• CLI argument parsing is more strict now; camelCase parameter versions like --packageDir are no longer supported; use their kebab-case versions like --package-dir.
• dropped Bower support
• dropped support for Node.js <18.3

Add basic validation of the packageManager option; document that it's not safe to pass untrusted input there.

• Always run the install command if prune is necessary.
• Unify the Windows & UNIX spawnSync code paths using shell: true where supported.
• Officially support Node.js 8 & npm 5

Drop support for Node.js <4