[ghex] build: Change header installation directory back to gtkhex-3

[Ting-Wei Lan <lantw src gnome org>]

commit 71a64b041dca4a170bc4d25bf41721dfd00b0756
Author: Ting-Wei Lan <lantw src gnome org>
Date:   Sun Apr 22 18:44:21 2018 +0800

    build: Change header installation directory back to gtkhex-3
    
    This is what autotools build used to use, and it makes it consistent
    with the .pc file.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=789118

 src/meson.build |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/meson.build b/src/meson.build
index fe34273..fdcdcc2 100644
--- a/src/meson.build
+++ b/src/meson.build
@@ -29,7 +29,7 @@ libghex_link_args = [
 
 install_headers(
   libghex_headers,
-  subdir: 'gtkhex-@0@.0'.format(libghex_version_major)
+  subdir: 'gtkhex-@0@'.format(libghex_version_major)
 )
 
 libghex = library(