Update ruby-ruby_parser to v 3.3.0. Tweak package.

Tweaks are significant. Some highlights:

* Add option `!emptydirs`. This silences a namcap warning.
* Update `package` function. Do not export `HOME` or set variable `_gemdir`.
  Instead, use variables where they are needed. (each var was used once)
* Remove md5sums array.
* Replace _gemname variable with _pkgname variable, to be more consistent with
  other packages that I (Jeremy "Ichimonji10" Audet) maintain.
* Trim down comments at top of file. Replace some double quotes with single
  quotes.