Bug fixes. Requires node >=16

• Breaking: Now requires Node v16+
• Enable extended globbing from minimatch. This means that some patterns will
  work in this version might not work in other editorconfig implementations.
  Fixes #84.
• Add unset option to API and CLI. When enabled, properties with the value
  "unset" will be removed from the returned object. Defaults to false in all
  cases, since according to the core team, this is something that the editor
  plugin is supposed to do, and the tests reinforce this. An unset()
  function is now exported if you'd like to call it explicitly.
  Fixes #123.