Log Message:
ruby-cairo: update to 1.16.5.

Upstream changes (from NEWS):

Release 1.16.5 (2020-02-03) Sutou Kouhei <kou@cozmixng.org>
============================================================

Improvements
------------

  * Added Cairo::Context#raw_address for integration with other
    libraries.
    [GitHub#59][Reported by kojix2]

Fixes
-----

  * Changed to use only ASCII for color name.
    [GitHub#57][Reported by spoolkitamura]

  * Fixed the number of arguments of the following methods:

    * Cairo::Surface#copy_page

    * Cairo::Surface#show_page

Thanks
------

  * spoolkitamura

  * kojix2