freetype: Update version from 2.7.1 to 2.8.1

The announcement [1][2] lists all the changes.

> ### FreeType 2.8 ###
> 2017-05-13
>
> FreeType 2.8 has been released. CFF2 support and OpenType variation font
> handling is now complete; the auto-hinter now understands 25 more
> scripts, for example N'Ko and Tifinagh.
>
> See here for a list of changes; noteworthy bug fixes are the handling of
> TrueType fonts: unhinted loading didn't work as expected, and the light
> auto-hinter used incorrect metrics.
>
> ### FreeType 2.8.1 ###
> 2017-09-16
>
> FreeType 2.8.1 has been released. This is mainly a maintenance release
> with one important change: By default, FreeType now offers high quality
> LCD-optimized output without resorting to ClearType techniques of
> resolution tripling and filtering. In this method, called Harmony, each
> color channel is generated separately after shifting the glyph outline,
> capitalizing on the fact that the color grids on LCD panels are shifted
> by a third of a pixel. This output is indistinguishable from ClearType
> with a light 3-tap filter.
>
> See here for a extensive list of changes; noteworthy bug fixes are
> correct handling of B/W TrueType hinting and some OpenType variation
> font handling issues.

[1] https://www.freetype.org/index.html#news
[2] https://lists.nongnu.org/archive/html/freetype-announce/2017-09/msg00002.html

freetype.be0

@@ -1,6 +1,6 @@
 #!/bin/env beesh
 
-# BEE_VERSION freetype-2.7.1-0
+# BEE_VERSION freetype-2.8.1-0
 
 BEE_BUILDTYPE=autotools