Log Message:
games/ruby-squib: update to 0.16.0

## v0.16.0 / 2020-11-24

Features:

* Special custom unit: cells. A "cell" defaults to 37.5px, or 1/8in,
  e.g. `x: '1 cell'` means `x: 37.5`.  See the docs for details.

* Shorthands for `x`, `y`, `width`, and `height`! The words `x: 'middle'`
  and `x: 'middle + 1in'` will get interpreted.  See the docs for details.

* Autoscaling text! `ellipsize: :autoscale` will now downscale your
  `font_size` if the text ellipsized.  Thanks @Qgel! (#288, #111).

* Option checking!! Completely reworked the way we handle arguments in
  Squib internally (no external behavioral differences).  Now, when you
  give an option to Squib that is not expected.  Since every DSL method
  "knows" what options it takes, that also means we have EVERY option
  properly documented (missed a few...) AND we have an automated test that
  will tell us if we forget to document it.

* `save_png` and `save_sheet` now have a `suffix` option which defaults to
  `''`.  So now you can customize the filenames with `prefix`,
  `count_format`, and `suffix`.

Compatibility:

* When saving PNGs with sprues, outputs start counting at zero - which is
  more consistent with the rest of Squib.

* Minimum Ruby is now 2.5. NOTE: Ruby 3.0 is coming Christmas 2020!! Check
  it out.

Bugs:

* Extra page/no page issue with sprues (#320)
* Fix Ruby 2.7+ deprecations with CSV arguments (#303)

Chores:
* Reorganized the code internally. (#298) Every DSL method now has its own file.
* Moved to Github Actions
* Bump pango et al