Log Message:
ruby-cairo: update to 1.17.7.

Upstream changes:
 https://github.com/rcairo/rcairo/blob/v1.17.7/NEWS

Release 1.17.7 (2022-07-31) Sutou Kouhei <kou@cozmixng.org>
===========================================================

Fixes
-----

  * Fixed a bug that Cairo::UserFontFace#on_render_color_glyph isn't
    called.

Release 1.17.6 (2022-07-30) Sutou Kouhei <kou@cozmixng.org>
===========================================================

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

  * Added support for cairo 1.17.6:

    * Added Cairo::PDFVersion::VERSION_1_6.

    * Added Cairo::PDFVersion::VERSION_1_7.

    * Added Cairo::PDFSurface#set_metadata.

    * Added Cairo::DirectWriteError.

    * Added Cairo::Context#set_hairline.

    * Added Cairo::Context#hairline?.

    * Added Cairo::UserFont#on_render_color_glyph.

  * Updated tests for cairo 1.17.6.
    [GitHub#75][Reported by Mamoru TASAKA]

Fixes
-----

  * Fixed a wrong conversion bug for the rest size argument in read
    callback.

  * Fixed a wrong conversion bug in Cairo::Options#hash.

  * Fixed a GC related crash bug in Cairo::Surface#finish.

Thanks
------

  * Mamoru TASAKA