harfbuzz: Update version from 1.4.5 to 1.4.6

From the [GitHub release page][1]:

> Overview of changes leading to 1.4.6 Sunday, April 23, 2017
>
> *   Graphite2: Fix RTL positioning issue.
> *   Backlist GDEF of more versions of Padauk and Tahoma.
> *   New, experimental, cmake alternative build system.

[1]: https://github.com/behdad/harfbuzz/releases

harfbuzz.be0

@@ -1,6 +1,6 @@
 #!/usr/bin/env beesh
 
-# BEE_VERSION harfbuzz-1.4.5-0
+# BEE_VERSION harfbuzz-1.4.6-0
 
 SRCURL[0]="https://www.freedesktop.org/software/harfbuzz/release/harfbuzz-${PKGVERSION}.tar.bz2"