freetype: Update to upstream version 2.10.2

[akien-mga]

Upstream changelog, not much directly relevant for us so I'm just updating for consistency:

CHANGES BETWEEN 2.10.1 and 2.10.2

  I. IMPORTANT CHANGES

  - Support  of  WOFF2  fonts.   This  code  contribution  was  Nikhil
    Ramakrishnan's GSoC 2019 project.


  II. MISCELLANEOUS

  - Function  `FT_Get_Var_Axis_Flags' returned random data for  Type 1
    MM fonts.

  - Type 1 fonts with non-integer metrics are now supported by the new
    (CFF) engine introduced in FreeType 2.9.

  - Drop  support  for Python 2 in Freetype's API reference  generator
    `docwriter'  (Python >= 3.5 is required for targets  `make refdoc'
    and `make refdoc-venv').

  - Auto-hinter support for Hanifi Rohingya.

  - Document the `FT2_KEEP_ALIVE' debugging environment variable.

  - The Visual C++ (and Visual C)  project files for Windows builds no
    longer generate libraries that contain the FreeType version in its
    filenames.   Instead,  a  resource  file gets  used  to  make  the
    libraries contain the corresponding information.

  - The next release will remove Jam build support.

  - The  `ftbench'  demo  program  has  a new  test  for  testing  the
    `FT_Glyph_Stroke' functionality.

[Calinou]

• Support of WOFF2 fonts.

This could be interesting for us, actually. WOFF2 font files are much smaller than their TTF or OTF equivalents, which can be important for mobile and Web games. All modern web fonts out there use this format.

I don't know how much work would it be to wire WOFF2 support into Godot though.

[akien-mga]

Cherry-picked for 3.2.2.

[Calinou]

I had a brief look at WOFF2. Since the format uses Brotli compression, we'd need to build the Brotli library into Godot to load WOFF2 files. At the same time, we could use this to benefit from compressed HTTP responses à la #38944.

Still, I don't think this is worth the trouble since nearly all fonts distributed as WOFF2 are also available as TTF/OTF files. WOFF2 fonts can be significantly smaller for the same visual quality, but we need to balance this out with the Brotli library code size.