CHANGES entry for COLRv1

CHANGES

  - New  API  was  added  for surfacing  properties  of  COLRv1  color
    fonts. COLRv1 color  fonts are a new proposed addition  to OFF and
    OpenType.    Specification     work    currently     happens    in
    https://github.com/googlefonts/colr-gradients-spec/.   COLRv1   is
    expected  to be  merged to  OpenType and  the ISO  standardisation
    process for adding COLRv1 as an amendment to OFF is underway.

    COLRv1  tables  are  mapped  to  the a  specific  subtype  of  the
    FT_COLR_Paint union. As COLRv1  fonts store drawing information in
    a  graph, often  a  FT_OpaquePaint  type is  used  to represent  a
    particular location in the COLRv1 table.

        FT_Get_Color_Glyph_Paint
          Retrieve the root paint for a given glyph id.

        FT_Get_Paint_Layers
          Accesses the layers of a PaintColrLayers table.

        FT_Get_Colorline_Stops
          Retrieve the stops on a color line for
          a color stop iterator retrieved from a paint.

        FT_Get_Paint
          Dereferences an FT_OpaquePaint and retrieves the
          corresponding FT_COLR_Paint object which contains
          deatils on how to draw the respective COLRv1 Paint table.